Should I ask him out?

Okay, I have liked this guy forever! I haven't seen him in a while, and I just turned 18. He is 30... (Yeah i know. Big age difference) I haven't seen him in a few years, but I've liked him forever. We used to email and stuff... But we haven't in a long time. I miss him so much. I never asked him out because I was under age, and that would just be creepy and illegal. So, now that I'm 18, I was wondering if I should shoot him an email. I'd ask him if he wants to catch up and go get coffee or something. Bad idea? As I said, I haven't seen him in a few years, so I don't know if he's in a relationship now... Or even married. Who knows! Bad idea?