Help me find cute nicknames for StepMom!?

I have been in my "bonus daughter's" life ever since she was 1 yr old, she knows I am not her mother but even though she knows my name perfectly well she insists on calling me Mommy, and I feel mean to tell her not to call me mommy, even though I have tried repeatedly to have her call me other than Mommy she won't stop, and I dont want to hurt her feelings or make her feel I neglect her(specially now that I have a newborn daughter), any advice or nicknames that she can call me please, thanks much! I really dont want to make anyone feel I am trying to replace her mother because I am not, I know it would cause me a great deal of pain if my baby were to call someone else Mommy, I think its just motherhood nature to want to feel exclusive in your children's life. Anyways please HELP!