In a lengthy career of mostly undiscovered crime, the only thing I've learned for sure is that you are never as sharp as you think you are; and that goes for ANY age! I seem to have sadly lacked the absolute certainties expressed by some Pruners here.
But by God I've had a good time and even enjoyed it; and luckily our fellow aviators will always puncture any false self esteem that may creep into our lives.
So, I say keep learning and remain suspicious of anything mechanical and any "expert" advice; stop when you've found something else to do and before gravity catches up with you.