My beau has a daughter. She doesn't remember a time in her life when I was not a part of it. She calls me her stepmom. Her friends and her friends' parents and my friends call me her stepmom. I could be. I should be.
I rationally know that I matter to my beau's daughter. I rationally know that she loves me and enjoys spending time with me and admires me and considers herself my daughter. I rationally know that the day will come--and, at this rate, soon!--when she tells me with so so so so so so much anger that I am not her mother. To which I will respond, "but I *am* your parent."