By Michelle Tauber and Simon Perry/London
Updated December 06, 2010 12:00 PM

Striding onto the world stage on Nov. 16, Kate Middleton gave a master class in princess-in-waiting poise. Sleekly confident and sweetly demure-with perfect posture and plum-pudding English tones-the 28-year-old brunette beauty radiated such natural charm that she seemed to the throne born. But aspiring princesses, take heart: Once upon a time, this royal bride-to-be wasn’t nearly so comfortable in her skin. As a young teen, she was shy and awkward. “She wasn’t really confident,” says a former classmate. “The poor girl, we felt sorry for her.” She gradually began to blossom in high school, excelling at sports and easily making friends. “She got on really well with everybody,” says another classmate. By the time she arrived at the University of St. Andrews, the timid teen was gone, replaced by a self-assured young woman with brains and pluck who knew exactly what she was looking for in a Prince Charming. “She was among a set of girls who were quite traditional,” says the friend, “where if they were going to have a man, it had to be a really romantic, sentimental thing.”

As the world now knows, she got her heart’s desire-and a kingdom to go with it. After eight years of dating, endless anticipation and, finally, an 18-carat sapphire-and-diamond engagement ring from Prince William, 28, Catherine Elizabeth Middleton is to become the future queen of England. It’s a thrilling, historic, “daunting” challenge, as Kate herself put it. And it begins right now. “There’s no charm school for princesses,” says Ingrid Seward, editor-in-chief of Majesty magazine. “It’s sink or swim.”

So far, she seems to be soaring. Not since the wedding of the last century, when William’s parents, Charles and Diana, married on July 29, 1981, have impending nuptials-the cake! the flowers! the dress!-generated so much unbridled excitement. And not since a 20-year-old Diana Spencer blossomed into the People’s Princess has a young woman so charmed her way into the collective consciousness. But despite the overwhelming hugeness of it all, those close to her say Kate’s glass slippers are firmly on the ground. “I’m willing to learn quickly and work hard,” she said in her post-engagement interview with ITN. In lieu of any formal coaching, she has been relying on her fiance to guide her. “William’s a great teacher,” she said, “so hopefully he’ll be able to help me along the way.”

For the most part, the biggest change in her day-to-day life since the announcement is the presence of a 24/7 security detail. She is not expected to take on any royal engagements in the near future and is instead focusing on wedding planning and her remaining months as a single girl living with her family in the quaint English village of Bucklebury. Of course there are perks to being betrothed to a future king, including the ability to appoint ladies-in-waiting (perhaps including her younger sister Pippa, 27), who will serve as personal assistants, as well as a private secretary. But friends don’t expect the glamour to go to her head. “She is a very honest and lovely person,” says one friend, noting that her spotless track record speaks for itself: In eight years as the most scrutinized girlfriend in the world, she has yet to make a single misstep. “The vast majority of girls in her position,” says the friend, “would have found it difficult to act as she has done.”

That integrity, say friends, has long drawn William to Kate since their earliest days as fellow art history majors at University of St. Andrews in Scotland. Unfailingly discreet, “she’s someone who’s there with him, to share his innermost secrets with,” says another friend. “I don’t know how many other people he can do that with.” But don’t mistake her quiet, polite manner for a lack of charisma. “While she’s not the sort of person who bursts through the door and grabs people’s attention, she very much has presence,” says the friend. “She draws attention to herself in a very unobtrusive way.”

Perhaps most significantly for the future princess is the fact that at 28, she is entering the royal family as a fully formed young woman. “With Diana, there was this desperation to get a girl who was clean and didn’t have a past,” says a family friend. “One of the reasons things went wrong [in Charles and Diana’s marriage] was because she didn’t have a past and didn’t spread her wings enough.”

Not so for Kate, who was able to enjoy college life at St. Andrews-and her budding courtship with William-largely shielded from public view. When asked at the couple’s press conference what he loves about his betrothed, Prince William promptly replied, “We have a great, fun time together,” adding later, “She has a really naughty sense of humor.” And she’s not afraid to let down that long chestnut hair: Observers say the girl who famously strutted her stuff in her skivvies before the future king of England while modeling in a student fashion show once mooned her schoolmates and has been known to drop a curse word now and again (in private company, of course).

But in recent years the couple’s wild nights out have given way to cozy nights in, and experts say Kate’s impeccable bearing will serve her well as she begins her new life as a royal military wife. After the wedding the couple will live in the white-walled farmhouse that William currently rents in a secluded, rural corner of North Wales, where he serves as a helicopter rescue pilot for the Royal Air Force. Experts say it’s unclear whether either William or Kate will be given new titles, especially since the title of Prince of Wales will fall to William when Charles ascends to the throne. “It might be considered that it is just not worth having a title for what would only be a few years,” an insider says. Once married, Kate is likely to join William on some of his 15 to 20 annual royal engagements; so far, palace officials have declined to comment as to whether she’ll join William on a pre-Christmas visit to the Centrepoint homeless facility, a charity supported by Princess Diana.

Keenly aware of the monumental shoes left by the late princess, she told ITN, “[Diana] is obviously an inspirational woman to look up to.” And yet as William quickly clarified, “No one is trying to fill my mother’s shoes. What she did is fantastic. It’s about making your own future and your own destiny, and Kate will do a very good job of that.”

Looking back, few might have seen Kate’s own extraordinary destiny in her unremarkable beginnings. The oldest of three children born to Michael, 61, and Carole, 55, who have been married 30 years and together run a successful party supply business, Kate enjoyed a loving childhood in Bucklebury alongside her more outgoing sister Philippa “Pippa” Charlotte and brother James, 23 (see box). Raised in private-school, ski-and-saddle privilege (though she’s allergic to horses), observers say she is utterly at ease with nearly everyone-with the exception of the paparazzi who follow her every move. Multiple sources cite the couple’s network of close friends-by all accounts a well-to-do, decent, fiercely loyal bunch-as a prime factor in helping to shape both Kate and William into grounded individuals. “He has grown up as one of the lads-as she has,” says the family friend. While Kate has maintained some close school friends, she has also taken on William’s chums as her own, including Thomas van Straubenzee, the son of a former military officer who is widely regarded as the prince’s closest confidante; Richard Branson’s daughter Holly; and Emilia d’Erlanger, a longtime royal family friend.

Still, insiders say that more than anything else, it is her closeness to her family that defines Kate. “It’s very important to me,” she told ITN. “We see a lot of each other. They’re very, very dear to me.” She has been warmly embraced by her future in-laws Prince Charles, 62, and his wife, Camilla, 63, as well as Prince Harry, 26, who calls her “a sister.” For his part, William relishes the stability of a classic, nuclear family. Exhausted from his training at Royal Military Academy Sandhurst, he would take his motorcycle for a ride to the Middletons’ expansive red-brick home about 30 miles away and crash with them, even jokingly calling his future father-in-law “Dad” and describing them as “really welcoming.”

Now that the two families will soon be united, the kind of under-the-radar privacy that William and Kate so treasure will be in increasingly short supply. Knowing the enormous pressure and scrutiny that awaits, William said that he took his time proposing to “give her a chance to back out if she needed to before it all got too much.” (Kate confessed that their brief 2007 breakup was painful but said, “It made me a stronger person.”) Having watched the implosion of his parents’ marriage and his mother’s struggles as a young royal wife, William noted, “I’m trying to learn from lessons [of] the past.”

To that end, the couple’s decision to live in North Wales rather than at a prominent royal estate signifies their determination to write their own rules for a successful marriage. Kate glowingly praised William as a “loving boyfriend,” saying, “He’s looked after me.” In fact friends say the prince handles their relationship with exceeding care. “Whereas Prince Charles immediately got on with business [after his engagement to Diana], William will be more protective,” says the family friend. “He’s a very kind and decent man. And he’s not as involved [in the monarchy] as his father was. William is much more natural and not so wound up with what he needs to do for his destiny.”

Still, for the union to thrive, “it all comes down to whether Kate and William have a clear plan for how they are going to work as a team,” says Patrick Jephson, Princess Diana’s former private secretary. What Kate will pursue in the way of her life’s work after marrying remains to be seen; having dabbled in retail fashion before joining her family’s business, she has been criticized in the past for appearing to lack a sense of purpose. But those who know her best, including her adoring fiance, have no doubt she will make her mark in a meaningful way. “Once the ceremonials and military stuff is done, I have always felt-because Diana once said to me-that William will carry on where she left off [with philanthropy],” says Diana’s former bodyguard Ken Wharfe. “Kate will be the perfect person to go along with that.”

In the short term, of course, she’ll also have her hands full planning a certain Really, Really Big Day-which more than a billion people are expected to watch. Before then the pair may spend Christmas apart, with William possibly having to report for work duty. But as they ring in the New Year, the couple will have a great deal to look forward to-including, in due time, the “happy family” they both say they would like to start. Meanwhile, much of the world eagerly hopes to witness the evolution of the woman who may just be the next People’s Princess-on her own terms. “I really hope I can make a difference, even in the smallest way,” she says of forging her own happily-ever-after. “You can only be true to yourself.”