Hi - Yes, you can have cancer at age 17. That said, it's very rare - about 1 in 2,000 chance. At your age, you're going through a lot of hormonal growth and body changes; since you're obviously stressed about your breasts, why not make an appointment to see the doctor? (S)he can tell you just what's going on with your body, and what (if anything) you need to do about it. So give the doctor a call soon, find a clinic, ask a parent to help you or the school nurse - just do something to set your mind at ease, OK? No need to live with stress when you don't have to! Good luck -PJH