I would recommend talking to a genetic counsellor. If you are still checking stuff out yourself there is also a risk calculator on the National Breast and Ovarian Cancer Centre (NBOCC) website that explains the different contributors to risk of getting breast or ovarian cancer and can give you an estimate of your risk, and ways to improve your chances (like breastfeeding).

Your risk and breast cancer - NBOCC
Yeah except it's actually a pretty crude calculator, by its reckoning I should still have 2 boobs.