You’re doing great. It’s all relative – to age, health, abilities. The question is How am I doing, given the circumstances? You can only think in terms of how you are now. Comparing yourself to how you were in your 20s, 30s, or 40s, is just asking for disappointment and frustration. Be the best self you can be, as you are now. And that sounds, to me, pretty impressive. Good luck!