The actress opens up about her famous eyebrows, why she's not afraid of aging and her best makeup secret

Ask Brooke Shields, the actress, model and beauty icon, about the world’s obsession with her famous eyebrows and she lets out a laugh. “I’m flattered,” she tells PEOPLE, “but it’s been so many years of that and when you get that label as a young kid, it’s hard to not think it’s ridiculous!”

“My mom would always say to me, ‘Don’t touch them,'” says Shields. “And [modeling agency owner] Eileen Ford wanted me to bleach them because I was blonde [at the time]. But my mom just said, ‘We’re leaving everything natural!'”

Brooke Shields Beauty

Jon Gurinsky

When creating her new namesake makeup line for MAC Cosmetics, Shields almost forgot to include a product for brow grooming. “I thought I’d covered everything: the lips, the cheeks, the eyes — what’s left?” she adds with a laugh. “I was so oddly forgetful because they’ve been talked about so much. But I realize that brow grooming is something that people focus on.” So she created a brow set (a clear brow gel). “I like the idea of filing them in and having a gel that doesn’t feel crunchy but keeps them looking good,” she says. “In the old days, I’d just lick my fingers, so I wanted to update that!”

The new line, a collection of 13 products (including a 15-shade eye shadow palette, lipsticks, glosses, blushes and nail polish) is available at MAC stores online starting today. The line’s colors range from fresh neutrals to reds and burgundies for fall. “I’m not just one person and none of the women that I know are just one version of themselves,” says Shields. “There are products for looks that are very natural and also sexy and sophisticated.”

Having grown up in the public eye, Shields, 49, speaks candidly about aging — the good and the bad.

“The toughest thing is giving up wanting to look like you did at 26,” she says. “Because when I was in my twenties, the fifties and late forties sounded ancient! Now I’m rapidly approaching that and I don’t feel ancient. I think that the toughest part is letting go of the past. But the easiest part is this feeling that this is who I am. It’s more important that I feel good than it is to have people think I look good.”

Besides, she says, “I definitely feel sexier and definitely more confident. I’ve stopped comparing myself to other people. Still I fall prey to it. But you just have to knock yourself and say ‘Nope, don’t do that.’ It’s just counterproductive.”

As for best makeup tip taught to her by a pro, she says, “When you put eye drops in, quickly breathe in through your nose because it sucks it back in and it won’t ruin your makeup.” [She demonstrates with a snort.] “You sound like a drug addict, but it pops right back in and your eye makeup doesn’t smear.”

Shields admits she wears more makeup these days. “When I was younger, it was such a job for me, so I would just wash it off the minute I was done with the job,” she says. “Now my daughter insists that I put makeup up when I take her to school. ‘Mom, please, at least put a little mascara on. And some lip gloss. And some blush.’ It’s like, ‘Anything else?’ So I definitely try to pay more attention.”

While her girls, Rowan, 11, and Grier, 8 “love makeup,” she says, she’s yet to have “the eyebrow talk” with them about not plucking their brows. “They’re too young,” she says with a smile. “I don’t want them to get conscious of that stuff.”

Are you excited about Shields’s new makeup line? Is she your brow idol? Share your thoughts below.

–Liz McNeil