How to get my niece and nephews to call me auntie.....i AM a girl but my avatar is a boy by accident.....?

My niece is 5, one nephew is 4 and the other is 1.....they are all talking but calling me by my first name only.....ill ask them whats my name n they'll say "auntie __(my name)___" but thats the only time they say it ......they dont call me that but they know thats my name.....how do I get them to cal me that all the time??? BTW; I AM a girl even though my avatar is a boy.....i neva knew how to switch the genders of my avatar