Narrative

Talking in third-person narrative. From what I can gather, I don't think this is very common, but it's something Penny's been doing forever. She knows how to talk normally, and uses the correct pronouns most of the time. What I mean is, she isn't making a mistake because she hasn't learned the right words. I can't recall her going through a phase where she didn't use pronouns correctly. Quite frequently though, she talks about herself in third-person as though she's narrating a story about herself. For example yesterday on the way home after dance class she took a sip of water from her cup that had been sitting in the car and had gotten hot. These were her exact words:
"As she was taking a sip of water, Penny realized that the water was too hot. She decided that she was not going to drink any more of it."
See? It's like she's living inside a book.
Sometimes I try to mess with her about it. She'll say something like, "Penny wants some ice cream." And I'll say, "Really? Penny wants some ice cream? Well, what do you want?" And she'll say, "I want some ice cream, Mommy," like I'm the biggest idiot ever. I mentioned this habit to her pediatrician and she just basically shrugged. So, I figure either she'll outgrow it, or become a novelist when she grows up. I'm just trying not to give her too much fodder for her tell-all memoir.