It's never too late to learn something new, no matter what your health situation is like.
Whatever you want to learn, there is a handbook for it or a course you can take. My favorite way of learning new things is to find people who do what I want to learn and ask to learn directly from them. Then I offer to teach them something in return (for example, I make a wicked 7-fruit marmelade). As long as I'm learning, I'm growing.
There's a Spanish saying that goes: "Dejar de aprender es empezar a morir"
which translates to..."To stop learning is to begin dying"
Nobody says you have to become an instant master at any new skill, but you can always start by learning the basics. What kind of things have you always wanted to learn? What's the first step you can take to do something about it?