I need relationship advice, for a gay teen. It's kind of complicated.?

So I met this guy on facebook, he is 21, and I am 15. We're both gay, and he is from Egypt and I'm in the US. We are great friends, and I feel like I'm starting to fall for him. He is coming to the US in three years to become a citizen, and he will live only 25 minutes away from me. Do you think I should pursue a real relationship with him, or should I wait until I'm 18? Should we just be friends for now, and then try something more advanced when he's here?