I'm 19. No health issues, but I have the same problem. It's like once you become an adult you're automatically feeling like you're in the body of a 70 year old man/woman.
It may be odd, but I actually really enjoy looking at this - people have a habit of taking ac as a game for little kids! (I'm also in the main quarter of people as I'm almost 15, heh.)
Also... I may be almost 15 (aLMOST) but my chronic health issues would actually suggest otherwise (I'm looking at you, knees that like to give out all the time)