Grandmother is nicknaming our daughter. Read description

My husband and I decided to name our baby girl, Dawson. We knew this was going to get some backlash from our family as it is not a traditional girl name. But everyone seemed to settle down on the name. Until recently I found out my husband’s grandmother, will not call Dawson by her name; instead is calling her Angel. Unbeknownst to anyone in the family, Dawson was the name of her husband’s late first wife. She did not tell us this until after Dawson was born.

I cannot stand the nickname Angel. But should I just let it go because she’s an older lady and it makes her happy? Or should I tell her I’d prefer she call Dawson by her name? Or should I suggest another nickname that doesn’t bother me so much?