You can never get too old.
Age is truly only in the mind.
Two cases in point:
1) My Government teacher was about 83. She's been asked to retired, and threatened to be fired, several, several times. But she's still going strong, still doing her job. She talks like a young person, she'll level with her students (18+, she teaches in college), and is hilarious. She's done like, everything and still doing more. She's incredible.
2) At my motorcycle safety class there was a 90 year old man there. Of course the instructors were worried about him but he said "son, I've been riding probably longer than you've been alive, I just want to get to know these new machines." then when asked why he would want to learn to ride he goes "I enjoyed it in my youth. And, the way I see it, I plan to live forever or die trying. So technically I'm still young." The way he put it was that if he was going to die he wasn't gonna do it in bed, while asleep. He'll arrive at the pearly white gates in a battered, well used body leaving a nice skid mark and yelling "****! What a ride!" (Paraphrased, I don't remember his exact words on that part).
Old people who don't give up are awesome.