I'm well into my 40s. I've noticed aging in almost all my friends and work colleagues my age as well as those up to 10 years younger than me. I haven't noticeability aged myself yet though. Don't have any grey hairs, no wrinkles, don't look older than I did in my 20s.

It's not just my perception either, other people assume I'm early 20s.

I can't really relate to the physical stuff though because muscle sores after training was always 3 days for me and it was always difficult to keep VO2max up, even in my early teens. So I guess I just started out in middle age.