BIG headed friend. Really upset me today. What do I do?

We were in English today and our teacher was telling us what our grades were so far. English is really important to me as I want to be a journalist and I hope to study it at university. Anyways, I got an A & B, she got two A's. When our teacher said B to me you should have seen her face, as if she was thinking..MUAHAHAHA I beat you!! She kept going on and on and on... telling everyone. I. don't. care!! She is always competing with me in everything! You should see her face whenever I do something good. It's like a pig's backside. She is driving me mad! She is better than me I admit it!! Grr!! Help!! Thanks :)