I speak Spanish with my kids in private and English if we're part of a larger conversation outside, but I haven't been able to call Munchkin "princess" in public. It just doesn't feel right. I see those annoying "Princess" t-shirts with crowns and glitter all over them and I don't want them to represent me or my daughter. Those shirts say, "Save me!" or they say, "I'm a spoiled brat," two things that will ideally never come out of my daughter's mouth.
Technically, there is nothing wrong with being a princess, or at least not a real one who does tons of charitable work, public speaking and represents her country. However, I find many issues with girls who fancy themselves as princesses, unwilling to lift a finger and unwilling to be kind to those "beneath" them. I'm not even a fan of the Disney princesses because so many of the movies revolve around finding a hero and/or a mate (usually one and the same) that I can't consider them role models. Being a fantasy princess seems to imply a sense of helplessness that no child, female or male, should mimic.
In a few years, Munchkin may want to wear princess dresses, tiaras and glittery shoes every day of the week. However, Munchkin is mi princesa not because she can wear elaborate dresses and sparkly shoes, but because she is tough, funny, smart and, above all, mine. She and Monkey--mi príncepe--are not the only things in my universe, but they are in the center of it. I run the household but these two rule my heart and thus, Munchkin is mi princesa, but not a princess. That is, unless she marries Prince William's future son to which, of course, I have no objections.