I felt I was good, meaning no noticeable decline in athletic performance and feeling great, until about 38. I was still going strong keeping up with my training program and competing but started becoming more conscious of my age which previously I really didn't give much thought to before. At 39 is when I started TRT. I really hit the wall when I turned 46. Nothing special about that number but that's when things noticeably started to fall apart. Everything from looks (wrinkles starting appearing), losing strength, recovery ability took a big dive, aches and pains constantly, always stiff and creaky, I've always been prone to injury but it got to the point where I got pretty fragile and I have to watch and limit some of the things I do. And there are now things I am simply unable to do. I probably do barely 20% of what I use to do because I've had to cut back so much. And still I drag. I look back and can't believe the daily program I use to follow. It would kill me now. Training 5-6 days a week twice a day. Hell, on Saturdays I would go to the gym from 8am-9:30am, then Jiu-Jitsu from 10-12noon, lunch, then Judo class from 2-3:30pm, and after hanging out with the team and eating and BS-ing until around 6:00pm I would go home and go at the heavy bag for about an hour. I was essentially training all day.
Physically speaking, it really, really does suck to get old. And you know it's only going to get worse.