As long as you still have a working memory, you can learn anything at any age, I don't go along with this 'old-dog-can't-learn-new-tricks' thinking. Though obviously when you're younger it's markedly easier to pick up a new skill.
It does take longer for many people to learn new things when they are 50-60 though. I do think we have to be realistic about the issue that many people who learned and performed complex intellectual skills in their 20s/30s no longer perform this kind of ability to pivot in their 50s/60s; to learn a new craft that depends on learning a lot of new information/skills. Of course this doesn't mean that all people in their…
I have a much wider framework of accumulated knowledge than I did 20 years ago, and leveraging that, I can see how wider parts of systems interrelate with a clarity that I never came close to touching in my youth.
Perhaps this too will fade in another 20 years, but so far I'm actually enjoying having a middle-aged mind. I can accomplish so much more than I could before.