Face your fears; express your feelings to him.
If you were to hold back until both of you graduate and get separated, you will never know what kind of response he would have given. You'll feel remorse if he would have told you that he felt the same way, or maybe not if he wasn't interested in the first place. Either way you both want to be together, right? Make an act to let him know before it's too late, otherwise you'll never know what kind of answer he would have given.