There is very good information on the internet re how to carry out a breast exam. Also your doctor should have literature that he could give you. If you really are very nervous, go to your doctor and ask him/her to do a breast check for you and then ask them to physically show you how to do one at home. At least then you will know that you are doing it right. Try not to worry, you have your whole life ahead of you, just be vigilant. Family history only accounts for between 5 and 10% of breast cancers, which is really not high. It would also be a good idea to speak to your doctor about your family history on your Dad's side, he may be able to give you some helpful information and put your mind more at rest. The best of luck.
You should carry out a breast check every month. You need to get to know what your breast feel like normally. Try not to do it when you have your period and your breasts can be tender and lumpy. I was diagnoised with breast cancer at 39 this year with no family history. A girl of 26 was diagnoised with breast cancer at my hospital this summer. I am not trying to scare you but anyone can get breast cancer, you are never too young or old. Start getting into the habit of checking your breasts, it won't do you any harm. Try not to worry about it, just always check yourself.