Time's Running Out...Should I Go For It?

First of all this is not one of those, "OMGZZZZZ DO YOU THNK HE LIKEZZ MII?!" questions, and I really don't want one of those types of answers. I'm looking for some unbiased advice here. I'm a junior in high school right now, and I've had a crush on my friend since the beginning of freshman year. The more people talk about college, the more I think about how I'll be leaving friends behind, but more importantly, how I'll be leaving this friend behind. I'm not sure whether I should ask him out or not, because I'm terrified of compromising the time we have together as friends with such little time left in high school, but I'm also scared of letting what could be an amazing relationship slip through the cracks. Does anyone have any advice on the subject, or has anyone experienced a similar situation? Any help is appreciated...this is something I would have trouble discussing with my friends at school for obvious reasons. If any other details are needed, just let me know. Thanks in advance.