Why am I always the friend?

You need to get with reality. Why do you wish you threw away an opportunity that can enhance your life, for a girl who isn't interested in you? Stop acting like a girl and just let it go. Girls like guys who are more ertive. While you flirted with her all summer, someone else swooped in and actually made a move on her. If you keep acting like one of the girls or their friend, then you will always be the friend.