Aaaaaaah! I have a teen!!

Okay, I think I'm starting to panic the more I realize that my son is a teenager. To me he is still my sweet & innocent little boy. I got a bit teary eyed as I wished him a Happy Birthday because I was already picturing him growing up & leaving me. Not too sure I'm going to handle that smoothly when the time comes. Seriously, how do I stop him from growing up so fast? I want him to be a kid as long as he can because being an adult is not as fun as it seems. What I would give to be a kid again!!!