“Old, but I'm not that old
Young, but I'm not that bold”

OneRepublic – Counting Stars Lyrics on LyricsMode
EXPLANATION
You think that your life is gonna fly buy but it wont because you are gonna life your life to the fullest but you are not much of a bright person. You can do dumb things sometimes.
EXPLANATION
They are trying to say that sometimes you might seem older than you are or younger but you shouldn't do stupid.
EXPLANATION
While the old may be wise, and the young may be bold, the song writer is neither, they are in the middle.
EXPLANATION
"Old but I'm not that old" means that he doesn't need that much help. "Young but I'm not that bold" means even though he doesn't need that much of aid, he still needs some. "I don't think the world is sold" and "We're just doing what we're told" means that even if what he is doing is wrong, he actually didn't mean to do the wrong thing.