It's supposed to be a cute trait (*1) when a girl talks in the 3rd person.
Kind if like how guys who talk in the 3rd person is instantly badass(*2).
*1: only up to a certain age, then it's just seen as childish.
*2: results vary. Common side effects are cringe, burning of right hand and sealing of left eye. Which could all result in dark history or (social) death. Use responsibly.