At 17 I had a major knee injury and it completely halted any aspirations of pro sports.
That slowed me down but didn't stop me.
At 50 I blew out the other knee, so now I have two blown up knees. Slowed me for a month but then I just got back on the horse.
.
I play racketball with leg braces on 3 times a week and get worked over by a personal trainer once a week. I still think young but my body tells me otherwise when I first get going each day.