BRCA Gene Mutation for Ovarian Cancer?

So I am 22 and am contemplating having this test done, to detect for ovarian cancer. My mother ped away from ovarian cancer, and she was diagnosed premenopausal. She was diagnosed at 42 and ped at 44. A few months ago my cousin (also on my mother's side) was diagnosed w/ ovarian cancer. She is only 35 so she is obviously premenopausal. So I think this test would be a good idea. But what happens if I test positive w/ the gene? Do I have to get a hysterectomy? What precautions am I to take?