I'm used to people thinking that I'm in my mid 20s (41). My wife is the same age as me, and she's got it even more. When we're out just the two of us and meet new people, and we mentioned our 10-year old kid, almost always right away we see them stared and did a double take to re-assess our age.
Anyway, I'm just enjoying this as much as possible now. Although I sometimes experiment with what I could do to look different. E.g. I found that a total buzz cut will cut a couple of more years, wearing a goatee adds at least 5, gaining some weight makes me look older, and vice versa losing weight makes me look younger, etc.
Thanks to my dad's awesome head of hair (which he still has full of, at 72), I'm not scared of losing anything up there, but the caveat is that they're solid white. He refused to color them, and when my time is come I would wear it with pride as well. He started getting his silver streaks in his mid-40s, so I should get them pretty soon too (some random strands are already showing pretty solidly).