Pray about it first; see what God says. He's still very young and might not be ready for dating.
But if you decide to go for it, I've found that men appreciate the direct approach. Talk to him about it; at least you'll know one way or the other if he's interested or not. If he's truly a friend, then that friendship won't be affected by the discussion.
In my first church when I was single I fell for a guy in the music team. We spent a lot of time together in a group. One day I plucked up the courage to tell him how I felt; he said he was sorry but didn't feel the same way. I was disappointed but gave it over to God and found my feelings changing back into just friendship.
If anything does happen between you, you owe it to your friend to tell her.
Jules