Your crush will graduate this school year, so you should get him out of your system by either going out with him or forgetting about him altogether. If you fail to do this, you run the risk of always wondering "What if?" Not knowing is tough. Don't do that to yourself.
You don't have to express undying love. Instead, get closer to him by asking if he'll be your "plus one" to an event large or small so that you don't have to go alone. Or ask him to do you a favor (e.g., give you some help in a class, teach you some skill he's good at). When we perform favors, we tend to like those who we have decided to invest in. It seems a little backwards but it's a real thing. Anyway, good luck. See if you two click.