Why on earth not? People these days live to well over 100, and monks in the forest live even longer
That means you've got at least 60 years to be in a band. My purpose is somewhat involved with that too I don't know exactly how yet... I feel the same purpose... you know, if you don't know music, just take theory books with you everywhere and instead of reading anything else, read that, waiting for appointments etc. They have computer programs that teach the essentials, painlessly. You can also start lessons if you don't already play something. I've been singing 'choral' style for most of my life, and lately I realized I want to learn to sing in a more commercial way, and got an on-line sls course, all I have to do is 45min every day, be in the 'now' while I'm doing it, and magically I have a new voice
(actually I sing longer than that, but that's how you start, and when you have time, you do more). ...seriously, it's just seeing what kind of band you can have, and how best to go about it. If you feel too old, take up meditation (for alpha brain-waves) and bikram's yoga to feel younger and have more energy (it's better than all other forms of excercise put together), get more sleep... you see, you can figure out how to do just about anything...
what do you play?