Would you be mad/ irritated?

So my daughter is 2 and a half years old and her name is Andrea. We started calling her Andy for short but that didn’t stick as my son couldn’t pronounce it so he started saying “Annie” instead. So since she was a about a month old literally everyone’s called her Annie. I think it’s pretty cute and don’t mind. I don’t even call her Andrea anymore at this point.

Anyway my brother in law had a daughter and named her Maria Anabelle. Idk why but they chose to call her by her middle name more than her first. That’d be fine except for the fact that they started calling her Annie as a nickname. Our families are very close so I asked why were they calling her that and they said because her middle name is Annabelle so they’ll call her Annie for short. Even though my daughter has literally been called Annie since she was a month old by everybody. I’m so bothered by this but idk if I’m overreacting.