I know what you mean, I had a couple of gray hairs at 28, but looking back, I think I was in my prime at 32.
My face had more character, but hadn't started looking 'old'.
I suppose one good thing is that even though I notice the fine lines and sagging body parts, others don't notice. And while really young kids can tell that I'm "old," I can get by with looking like I'm a little younger with having long hair and when wearing jeans and the right kind of shirt (no sparkles or crop tops though!).
Earlier this year, I was at the dentist for a standard teeth cleaning, and the topic of my retainer came up. The hygenist said that it was rare for kids my age to still have retainers when they are around 21 or 22 because most quit wearing them when they are in college. I told her that I'm thirty, but I took absolutely no offense to the comment. :-)