Family history of breast cancer, when to get a mammogram and ultrasound?

See below. If you have a first degree relative (mother or sister) who was diagnosed at age <50 then take the age at diagnosis and subtract 10 years. So if your mother was diagnosed at age 46, you would start at age 36. Otherwise, all women should start annual screening mammograms at age 40.
Know history. It is important to find out the ages of family members who have breast cancer. If it is a mother, sister or grandmother who was diagnosed before age 50, then you may need to start 10 years prior (i.e. If mom was 42, then start at 32). It also important to have a risk assessment and find out if there is any brca mutation in the family.