Michelle Obama at 50

“WEAR COMFORTABLE SHOES.” That was the President’s directive to guests for his wife’s Jan. 17 birthday dance bash – but it could easily be Michelle Obama‘s motto for her next half century. In a candid chat with PEOPLE’s Sandra Sobieraj Westfall, the First Lady, on a prim Blue Room settee, fairly bounced with energy as she talked about her upcoming milestone and the wide-open possibilities for her life outside the White House. “That’s when I can really roll up my sleeves,” says Mrs. Obama, who was a lawyer and hospital executive before her husband’s political career. But first, a celebration! Mrs. Obama, after the family’s traditional Hawaiian Christmas, lingered for a girls’ week with close Chicago friends plus Oprah Winfrey and Gayle King at Winfrey’s home on Maui, where they hiked and enjoyed sunsets from the porch. So far, there’s been no getting-old grousing from the birthday girl. “Michelle’s all in on turning 50,” says pal Valerie Jarrett. Adds Democratic strategist Donna Brazile: “Michelle is still writing her story. I can’t wait to see the records she’ll set. And can she ever still shake a tail feather!” As for the party-planner-in-chief, her husband tells PEOPLE (unashamedly, with Michelle nearby), “I’m always in awe of her.”

You’ve said that as a girl you didn’t want to peak in high school. Has Michelle, here at 50, peaked?

MRS. OBAMA: I don’t know. I mean, I’m the First Lady of the United States of America – that’s pretty high up. But I’ve always felt like my life is ever-evolving. I will be in my early 50s when I leave here, and I have so much more that I should do. I don’t have the right to just sit on my talents or blessings. I’ve got to keep figuring out ways to have an impact – whether as a mother or as a professional or as a mentor to other kids. When we leave here, Malia will be in college; Sasha will just have a couple of years left, and then she’ll be in college. At that point in life, whoa, the sky is the limit!

What don’t you miss about your 20s?

MRS. OBAMA: I’m more self-assured now. Each decade just brings a greater sense of calm and certainty and maturity and confidence that there’s just no way you have that when you’re 20. I knew nothing in my 20s, [but] I thought I was pretty smart. As I watch my mother, who is 76, she’s even that much more solid about herself. She speaks her mind. She does exactly what she wants to do every single day without apology. I’m not there yet, but I look forward to that.

Are there are other role models you look at and think, “When I’m 70 or 80, I want to look and live like her”?

MRS. OBAMA: Oh, yes. Every event I go to, every rope line, women are looking better with every passing year. I run into women all the time who will just happen to mention, “Oh, I’m going to be 60,” and it’s like, “You’re kidding me!” I just went to see Cicely Tyson on Broadway. She is in her 80s and did a two-hour play with stamina and passion. I told her, “I want to be you when I grow up!” [And] there’s Jane Fonda, a beautiful, engaged, politically savvy, sharp woman.

When the nation first met you, “Michelle Obama arms” were all of a sudden a thing. Do you feel pressure to keep up that toned look?

MRS. OBAMA: There are definitely times when you just don’t want to be on, for sure. Everyone has those days. I am my primary judge, the person who I have to satisfy. I don’t feel pressure to satisfy other people’s expectations. But I have high expectations for myself. I want to feel good, and I want to be as healthy as I can be because I want to be able to enjoy my 70s and 80s.

When do you think, “I am getting old”?

MRS. OBAMA: Well, there are those times when your staff tell you they were born the year you were graduating from college. It’s like, really? Really? That hurts. [Laughs] But I don’t feel that much differently than I did when I was younger. My message to women is be healthy. I make sure that I am up on my checkups. I have never missed a mammogram or a pap smear. I’ve had a colonoscopy. I don’t obsess about what I eat, but I do make sure that I’m eating vegetables and fruit. And as everyone knows, I do exercise. I’m seeing myself shift from weight-bearing stuff – even though that continues to be important – and the heavy cardio and running, to things like yoga that will keep me flexible.

Do you have a philosophy on plastic surgery, Botox, fillers?

MRS. OBAMA: Women should have the freedom to do whatever they need to do to feel good about themselves. Right now, I don’t imagine that I would go that route, but I’ve also learned to never say never.

Anything you won’t wear anymore? Do you ask, “Is this age-appropriate?”

MRS. OBAMA: I do think that when you try to dress like you’re a 16-year-old, that can make you look older than you are. So I tend to focus on things that I think look good on my body. I have long legs; I have hips. My shape is different from the vast majority of women’s. What I have learned to do [is ask], “How do I feel in it?” As you get older, you start understanding what makes you happy and feel good and going with that rather than following the fashion trends or trying to keep up with your teenage daughter.

Is menopause something you and your girlfriends talk about?

MRS. OBAMA: Oh, yes. Because I have friends in varying stages of it now, as my friends move into their 50s and 60s, that’s a topic – what that feels like, do you take hormones, and what are the pros and cons of that. I talk to my mom. She’s like, “Menopause? Yeah, I think I went through it.” It’s like, “I’m sure you did, Mom.” [Laughs]

What do you dream of doing by 70?

MRS. OBAMA: There’s this book we had on our coffee table of the 100 most beautiful places in the world. I thought one day, “I want to look at a spot and say, ‘Let’s go! Let’s go to that castle in Ireland that’s in a remote spot. Let’s do that rafting trip.'” I want to see the places that make this planet beautiful. Many of those are right here in this country. I still haven’t seen the Hoover Dam. I have flown into an airport, done an event and left, but I want to stay and have a meal, try the local dish and shop in a little shop.

What kind of grandma will you be?

MRS. OBAMA I want to be the grandma that my mom has been. I want to be there for my girls, and help them be mothers and women and achieve their dreams. What if Malia has this great career and a new baby, and she doesn’t feel comfortable putting her child in child care? If I have the time, yes, I’d love to be able to pitch in and be there when she’s struggling with those first few years and months of panic and confusion. I want to be that grandma. But I also might be still peaking. Maybe I’ve found a really important project that I’m passionate about, and I’ll have to balance it all—being a good grandma with doing the work I care about. So I have actually started thinking about that, not because of my age but because I’m watching my girls grow up right before my very eyes. They are now at the age where I can envision them going off to college and getting married and having kids of their own.

Your mom could still help –

MRS. OBAMA: At that point she’ll be like, “You’re on your own, kid; I am done!” I think after this, she’s done with all of us. [Laughs]