How do I tell him that I like him?

[Hannah]

So I met this guy at band camp, we both play drums for our high school marching band. When we met, I was 13 and he was 16. I thought he was the hottest thing that ever walked this planet, minus the sun burnt face(; well, I was always scared to talk to him, so I grew a pair and messaged him on Facebook. We would talk for a long time, often, but he wouldn't talk to me for real, even though I never tried. His friends were older and we ran in different circles. Well, our chatting died and he's in college now and I'm only 16. (He's 19) our Facebook chatting died out for the most part and I want to tell him how I feel. I've liked him a lot for 3 years. How do I tell him? How do I even bring up the subject? How do I start that conversation? When do I tell him?
Addition*

It's not that he's not into me, and he contributes more than I in conversations. It's just that when he went to college, and was looking at colleges, applying, applying for scholarships and so on, he got to busy to talk to me and I knew that, so I slowed down talking to him ^_^
Addition 2*

Age of consent is 16