Trixie is the name of the baby in the comic strip Hi and Lois. She thinks mature thoughts, though of course she makes childish misinterpretations of things.
Trixie Lulamoon is a character in the cartoon "My Little Pony: Friendship is Magic". She is an obnoxious, boastful stage magician unicorn. (A fitting name for someone who does "tricks".)
There was a fictional character named Trixie Belden, who used to solve mysteries with her best friend Honey, and the rest of the Bobwhites (their club). I enjoyed reading those books, but I would definitely not name a child this.