Ignorant Question, but is Teemo a child?

I've noticed that a lot of Yordle voices sound much more mature compared to Teemo. I'm aware that Teemo is an old champion, but his voice hasn't been touched in a while, apart from Omega Squad.

If you compare Teemo to Rumble, it sounds like Rumble is much older than Teemo. (Incidentally, how many human years is considered one Yordle year?)