I feel that Link is naive at heart in most cases, espesually the young encarnations of him.

He is gifted with courage, and is willing to help anyone in need. This fates him to be the hero of others. He thinks nothing of reward, he is doing what he is asked simply because he is asked to do it.
Even in the elder encarnations of Link this remains mostly the same. I speak really, only about Twilight Princess' Link because Ocarina Of Time's adult Link was actually just the same child locked in his own, older body, therefore still retaining that childhood innocence.
ANYWAY -- An older encarnation of Link would of course be more experienced in the ways of the world around him, however, he is raised to work hard, and act on his promises with no hope of reward, so in this way, even though he is more mature and most-likely thinks as such, he still has the urge to help and do his job, be he a hero or not ( and he DOESN'T see himself as a hero regardless ), with no regard for his own safety, or any kind of reward once he is finished.