Mk is right. Tell your Mum that with your family history of breast cancer, you would feel a lot better if a doctor showed you how to examine your breasts so you can learn what is normal for you, and what is not. They quite often don't start regular mammograms until a woman is 40... until then, you need to know what you are feeling when you do an exam. Most of the women here who had breast cancer before age 40 found their cancerous lumps on their own. (I'm one of them!) This is important! So don't let your mum discourage you.
"There's a difference between a philosophy and a bumper sticker." --Charles Schulz