Girlfriend going to college?

My girlfriend and I have been together a bit over 2 years now, and in September she will be going off to college and I will be a senior in high school. It isn't that far away, about a 45 minute commute by train, but we won't see each other nearly as much as we do now. Also, I will be taking 5 AP classes and playing soccer. She's really worried that we are going to drift apart and I can't blame her because we both know that I'm going to be very busy. I try to be optimistic whenever we talk about it and say that everything will work out, but as it gets closer I'm starting to have doubts. Anyways, we're obviously going to stay together as long as we can and I don't see myself wanting to break up with her but I don't want to drift apart and not be able to make time for her. I really hope that things work out but what do you guys think? It isn't crazy to think that we can stay together, right?