Hi Vickie....sorry to hear of your sister's diagnosis, hope she is well. People can and do live long long lives after breast cancer and never have to deal with it again. Most breast cancer, I think around 90%, is not "inherited." If your sister is young and there is other family history of breast or ovarian cancer, talking to a genetic counselor to determine risk for other family members may be warranted. But remember that 1 in 8 get BC, and sometimes it just happens.
You should definitely be screened with routine mammograms and breast exams, and be sure to let them know that your sister has BC.