Birth control?

I'm 12 and I started my period when I was 10, at first the pain was so bad I was throwing up and I even passed out, as time went on I got used to it but the pain never lessened, I have my period for 5-6 days and 4-5 of those days is just pain. I get pain before and after my period too, my friend (5 years older) is on birth control and she says that her period is once every three months but my mom (a biologist) says that birth control can cause cancer and I'm worried, she thinks it's a good idea but I'm too young. Help?? (I'm talking about the pill)