I grant that Timothy was told "Let no one look down on your youthfulness, but rather in speech, conduct, love, faith and purity, show yourself an example of those who believe." Still, it seems as though most of history, in the church and out of it, it is elders who teach.
Why are youth group leaders so young? I know the theory is that they are better "able to connect and communicate," and it is certain that they've got more stamina, but when I was that age I thought I knew more than I really did--and quite a bit of what I did know was theoretical. There's something about being able to say "I've seen this fad before, and it doesn't help anything."
I think I persuaded our youth group leader to have a look at my Background for the Faith (currently rough and uneven). If he wants me to introduce a few modules, I'll ask if he's also interested in the concept of "Ask a Grandpa" for confidential questions.