How tragic that at the gentle age of 52 the question of age should even raise its head!
My mother made it up to about 93 or so and she was always convinced that, inside, she was still twenty-something. I'm trying very hard to emulate her in that respect, though I'm not quite convinced that reaching the goal will bring its own reward. But, having her attitude as long as one is still on the merry-go-round is no bad thing.
And neither is your fear of being the guy investing time in his craft for no good, ultimate, reason. The hell with the world at large: as long as you are happy doing what you do, that's all that matters. Who last asked you for your views on how they should run their life? Exactly! Do it for you!
;-)
Rob C