I'm older than most here, I imagine. Here's some things I began to learn at different ages:
By 16 I already played a number of musical instruments.
17 I began learning how to work in recording studios.
25 I really got into computers.
28 I began martial arts. I've trained ever since, and teach as well.
28-35 Read about 3000 books.
30 I began learning Danish and lived in Denmark for quite a few years.
30 I began to learn to really cook. I've kept it up, and can cook about any cuisine.
40 I learned HTML, web design and publishing. I still do that.
40 I really focused on learning the craft of writing. I still do that.
Along the way, I've kept up with music production and recording technologies every step of the way.
I think as I've aged, I've actually gotten better at learning with more focus.
Heck, sex even gets better.
Fear not. : )