Is it true if you had a maternal aunt with breast cancer you are more likely to get it?

Yes: Which aunt does not matter; any close relative having had breast cancer suggests a genetic predisposition. Especially if it came on early, consider being checked for brca1/brca2.

True!: Yes. Family history of breast cancer in second degree relatives increases the risk of breast cancer but only modestly. Family history in a first degree relative is a much stronger risk factor. In addition, if the family member is diagnosed younger age, the risk is higher than if he/she was diagnosed at older age.