Should i let her call me mom ?

just here recently me and my husband began to get his 11 year old daughter again we had lost contact with her and her family but now she is coming over again often and the other day i had my mother over we was having a cookout and she asked me a question and refered to me as " mom " i was kinna stunned i thought maybe she got names mixed up but i didnt say nothing then my mom relized she was doing it as well ... i was gonna tell her to call me by my name but my mother told me that i am her stepmom .... but parents aint always right i do know she calls her mothers husband "dad " at the age 11 should she beable to decicde what she wants to call me i guess im ok with it as long as she is comfterble with it is it wrong ? my stepson calls me by my real name because he was so little i didnt want him to forget his real mother even though she never comes around any i love her and im glad she likes me but i just feel wrong i dont know maybe bc i nevr had no one esles child call me mom but myown