I'm a huge advocate of living well and feeling great.
A forty-something (or a woman in her fifties or sixties) who works out tirelessly and has great legs should show those gams off. Liza Minelli, 68, shows off her assets, and so does Jennifer Aniston at 45.
Some women in their 40s look a whole lot better than girls in their 20s: They have higher incomes, more experience with dressing and one thing money can't buy: confidence.
Thirty-somethings should enjoy fashion. Wear whatever you want as long as you feel proud. It's not about the trend, it's about how you feel. Wear what speaks to your life: If you love jeans, pair them with sky-high heels for an edge. Guys also like gals in T-shirts, since there's no pretension there.
Let's switch gears to twenty-somethings. I'm not a fan of Hervé Léger bandage dresses, even for women in their 20s -- they only look good on supermodels. I do, however, love this sexy look: a tight skirt and a tee with open-toed, heeled sandals.
For twenty-somethings who are wearing Valentino or other serious designers, I can't lie: If you aren't buying it for yourself, you shouldn't be wearing it. If you are a killer hedge funder buying your own Hermès Birkin bag, show it off. But if Daddy bought it, or a sugar daddy, hide it.
And if you can't afford the labels at full-price, hit great vintage stores like Resurrection (217 Mott St.) and Allan & Suzi (237 Centre St.). Zara, Club Monaco and H&M are also amazing with trend-driven clothes that don't cost a lot.
Be proud of your age and the woman wearing the clothes, instead of trying to be something you aren't.
Follow Kelly on Twitter @KellyBensimon or visit kellykillorenbensimon.com