It's just another sign that she's not a little girl anymore. She used to have "cute" names for her grandparents-Nanna and PopPop. Those were hers; not prompted or taught to her by adults. The adults also referred to them that way to acknowledge her "speak". They were unique to my parents and we always knew who she was talking about. Well, just this past week things changed. I told her Nanna was coming in the morning to get her and she looked back at me and said, "Grandma coming?" I was too sad to even answer her. She still goes back and forth, but each day it's becoming more "Grandma/Grandpa" and less "Nanna/PopPop". Being a parent is crazy. You are so glad she is becoming more self sufficient and independent while at the same sadden that she's no longer a baby...she's a big girl!