That's an awesome goal. I have so much respect for people who just stay fit all their lives. I am so happy I didn't burn out as an athlete in high school or college; lifelong fitness is so much more meaningful than an emphasis on being competitive at a young age.
Fred Beckey is one of my fitness heroes. He is 91, and I'm pretty sure he still climbs harder than I do.
http://tylerroemer.com/gallery/original/fred_beckey_yosemite...