I'd stay with what you enjoy. At 30 I could learn something once and have it stick. No need to review, didn't forget. At 65, it sucks when I learn something

I'd stay with what you enjoy. At 30 I could learn something once and have it stick. No need to review, didn't forget. At 65, it sucks when I learn something one day, and have to refresh myself the next day if it was complicated. But I felt useful and productive until sixty. Everyone will be different, of course.