RE: When I was young I could [fill in the blank].
I discovered the hared way that one doesn't get old. It happens slowly and goes almost unnoticed until, in my case at least, everything physical gets more difficult. I had just bought my present house when I was your age 14 years ago. I worked my ass off clearing brush and painting etc and still had time and energy to go camping and hiking with the ex. I'm almost finished cutting my last log-length of wood. Every year the rounds get heavier and I have less energy to keep up with everything else that needs to be done. Anyway, you get the idea. Only thing I can say is that getting old beats the alternative and I'm grateful that I have the opportunity to experience it. I know, make that remember, too many people who didn't get the chance.
Keep at it. When you stop that's when the wheels of time speed up. I'm grateful to older as well.