I'm in the same boat. At age 69, I look back at what I did in my 40's and 50's and realize those days are never coming back. I still consider myself a good cyclist but not a fast cyclist.

My motivation took a huge plunge in 2011 due to a number of reasons I've discussed here. Also, a few years ago my doctor told me I have a leaky heart valve. He thinks I had rheumatic fever as a child and probably didn't even know it. That's probably one reason why I've never been a strong climber.

Your last paragraph describes me quite accurately, except that I am already retired.

Does your weather allow you to train outdoors during winter? I'm looking forward to spending most of the winter on my trainer.

Best wishes, stapfam.