I'm around your age and I speak from personal experience when I say it is hard to get over a crush, especially when there is the pressure of being a teenager and also being 'free' for the first time.

It's a big world man, and I think you should try to move on. My first ever 'real' crush happened earlier this year. I left her a box of chocolates on Valentine's because I am a sappy idiot (also because my friends were going to pay me extra for buffing up if I did it), and it caused a social shitstorm. There were weeks when I couldn't even walk into a room at school without people teasing me about it. Long story short, she cut off all contact and even to this day refuses to talk to me. Even when I try to be nice to her (one time she dropped something behind at the library and I picked it up for her), she would get visibly angry at me. I later found out this was also partially through the scummy moves made by her friends (lying to me about her, lying to her about me), I was left put off and tired for quite some time. It didn't help that all the drama started right before exams as well. There were some days when all I could do was think about this girl, and realize that it wasn't even worth my time.

Now I've mostly moved on from her, and there are other girls I'm friends with who still occasionally tease me about this girl, along with my other friends. I figured out these girls were more worth my time, but I'm not going to jump into any relationships yet.

My mother, a wise woman, once told me that there are two types of ways a guy can have the world see his relationship with a girl during the teenage years. A 'friend', or a 'girlfriend'. If you guys stay friends, even if the feeling is one of mutual attraction, you can wait until later on in life before you truly date, after you've completed your education and also get a job to sustain yourself and possibly that special someone in the future. If you refer to them as your 'girlfriend' early on, you guys either have to stay dating forever until you get married, or the relationship gets fucked up. At around 15, I don't think I'm ready for that yet, and I'd assume you aren't either. I have some good relationships with other girls I don't wish to screw over.

I'm rambling on a bit now, but my point still stands. You don't need to rush with this. Take your time, consider your options, and even then, if you are happy with the way things are, there's no need to put pressure on the relationship with strange social concepts like 'girlfriend'.

Good luck, man.