I get a real lift out of teaching , maybe more than most other things I do, except playing for dancers and jamming with other musicians. Learning should be a lifelong endeavor. In the course of teaching musical principles to my students, I learn at least as much as they do. People often ask me if they are too old to learn a musical instrument. They are 40, or 55, or 75, and my answer is always the same.
Banjos are a way to stay sane.
I've never tried the tenor banjo, but 5 string clawhammer basics are easy to learn and there are several good video tapes available to instruct you if you can't find a good instructor. Your chances of quitting will increase greatly. If possible, find an instructor YOU LIKE, or find people to play with to keep your interest up. Buy a banjo. Make music a part of your life.