Welcome to the real world. And learn to just deal with the bitch, you're only going to have to deal with her for so long. High school doesn't last forever, and I hope to god you're just in high school, because by college I pray that you would have learned that petty shit like this doesn't even matter.
Errrr....yeah Doesnt really sound like it has anything to do with her being gay, or your looks. Just sounds like a pissing contest really, you are both alpha females in your own way, just butting heads. From what you told me there, if that was two guys, its the kind of thing I'd expect to be settled with a punch up after school. BTW, you hair looks a lot better in the 3rd pic, the headband thing is a bit too 80s, and some may think you're just trying to cover a zit or two, or at least not a dark colour one draws attention away from your hair, and you have cool hair so dont. Sorry, can resist the fashion advice