Need to talk about getting a girlfriend?

ok im 16 and really interested in getting a girlfriend. i have not had one yet and im told im nice and not bad looking. I know whats to blame and thats my school friends. some of my friends i hang about with are cool but some just make us all look bad, e.g. 2 of them do this thing where if they see a girl walking past them in the corridor on their own they will shout "slut" at them. that seriously destroys my rep. Im not saying im perfect and its just my friends cos im sure i have many faults also, but i just cant seem to get a girlfriend. Im going to college next year so hopefully things will change. There is this one girl i really like and talk to, but i found out she has a boyfriend and i feel quite **** right now :( my "friends" wont stop the "slut" thing, and its too late to find new ones.