Her hair is dyed, her mom dyed her brown hair blonde after her parents got divorced because her dad has brown hair and it reminds her of zoeys dad. And since zoey was so young when this happened she didnt know she had brown hair because all of her childhood photos(most were with her dad) were burned so she didnt until she went her dads and he showed her some of her childhood photos
(Zoeys dad isnt a bad dude zoeys mom just doesn't like him)