I'm so glad you asked. I just turned 80, and even though I don't have the stamina or strength I had when I was 40, I've kept up my mobility through (more or less) regular exercise. As the old joke goes, if I'd known I was going to live this long, I would have taken better care of myself. My only saving grace has been (semi) regular exercise and a (semi) good diet.
And yes, since you asked, there definitely are some advantages to aging. That's why it's a good idea to stay in shape to enjoy them.