I dunno, I always had the impression C.C. was more....ladylike? Not the word I'm looking for but whatever.
And I wouldn't call her immature if that's what you mean. Cheese-kun just came with her pizza obsession, it's not like she loves toys in general (I seriously doubt that). Plus it was only supposed to be a 'cute' side of her, since C.C. is generally not a cute character imo.
You know, little aspect that makes her more dynamic or something
And didn't Amber just get younger on the outside?