You kids are so cute. You're not going to believe you even made this post in another 30 years or so. Believe me, 40 feels just like 20 only a little slower and with hangovers if you drink too much.
I'm 43, have had a fair amount of time in the company of horses, Western trail rides, etc. and I just took up hunt seat in a moderately serious way.
The older you are, the better you listen. The longer it takes to put things back together after you fall, but the less likely you are to fall in the first place (because, believe me, knowing that a fall can wipe you out of 2 months of summer riding is a powerful deterrent to the kind of behavior that gets you into falls in the first place).
If you are the kind of person to ask "Am I too old for [insert activity here]?" instead of saying "Oh, no, I am too old fer [activity]" the answer is always going to be the same: No, you are not too old. (And to be asking this question in your 20s, which is your total physical prime, is...well, you'll appreciate the humor in it later...if you remember, that is.)