You may be chasing a dream! If you're not careful you'll find he gets into your head and you can't shift him. I'd suggest backing down a little, however difficult it may seem, or you'll cause yourself a lot of pain. There is nothing worse than unrequited love! It's very painful and upsets your equilibrium.
Don't buy him a present, ask him out for a birthday drink - perfect opportunity to get him away from studies and into a relaxed social environment with just the two of you, but I suggest you look at him as just a good friend, until you know different
One thing to remember, a good close friend lasts a lot longer than most lovers, and can be far more rewarding too !