Please Help?!

There's this boy that I'm really into and I've liked him longer than I've liked anyone else but I'm to nervous to talk to him. Everything about him is perfect, he's stupid, smart, funny but I've only really seen him socialise with people he really knows (not that I have a problem with it). He's in my English class and he sits behind me but I cant help but make a fool of myself with my best friend! There's a mirror on the opposite wall so I just look at him from there instead of doing my work. Just seeing him makes me happy but I just wish I had the nerve to talk to him :(   HELP?!