My boyfriend's 5 year old has started calling me mommy. This isn't something him nor I pushed. I've…

My boyfriend's 5 year old has started calling me mommy. This isn't something him nor I pushed. I've always been called Sam when it comes to her. We were in Wal-Mart and I was down the aisle while her, Raven (mine and bf's kid) and boyfriend were at the end. She comes running going "Mommy where are you?" and sees me and says "There you are!". I seriously thought she had seen her mom go down an aisle and was going after her.