Well, I know a gent at my old flying club who, for his 80th birthday, treated himself to a trip to Florida to get his multi rating. Don't know how long ago that was (at least three years) and I believe he's still flying.
Retirement age of 60 is probably more a political thing than medical, but it's also a hotly contested issue on which I wouldn't want to even enter a discussion.
Point is, if it's for fun and the brain/body is up for it, go for it regardless of age. What's age got to do with it?!?!?
Pitts2112