Dude, I was in the more or less the same situation as you during my first year at university. I found this girl I really liked in the first few weeks of university, barely knew her. Became good friends, but then she started dating this older guy in the 3rd year, who I had only met a week or two beforehand (this is where my story differs from yours).
So.. I just gave up on her and just tried to continue being friends, but because she was always with her bf, I knew I had to stay out of their way. I did what I did, cuz that's my character, giving up easily.
Fortunately for me though they broke up after a month, but I didn't start dating her until towards the end of the academic year (May), and by then, we were best friends.
My word of advice is give it time. See how things unfold. You can learn alot just by observing.