Even though you have known him for a long long time, you haven't known him like you do know. You know how he is in friendship, but not in a relationship. My advice is to wait.
I waited a year and a half to give mine up to my boyfriend who treated me amazingly and was my best friend... and he ended up breaking my heart by cheating on me with a girl from a completely different city and didn't tell me about it for 2 months- so I had to guess or he wouldn't have said anything.
I know that doesn't have to do with your situation, but all I'm saying is that waiting is the best thing to do just to see how they are in a relationship first and to just make sure that your feelings are legit and not just infatuation in a perfect disguise. I wish you the best of luck in this relationship though.
