I hope in this case, "girl" is referring to the condition of being young--girl vs. woman--rather than the condition of being female--girl vs. boy. Because I know boys who read like this.
Heck with that, I know grown folks who read like this. Like me! Okay, maybe I am pickier than some kids sometimes (*cough*Eragon*cough*) but I think the author is setting up a false dichotomy here, one that annoys me. She points to one daughter's reaction to an old favorite of hers as proof of the girl's growing "adult" skepticism.
“I couldn’t stop reading it,” she said, before adding, with regret, “but I knew from the beginning how it would turn out.”Yes? And? Like we didn't know at five years old how Sleeping Beauty would turn out? Or Harry Potter at twelve? Just because a kid recognizes the essential drive of a narrative--good guys/gals win, get the gal/guy, live happily ever after--doesn't mean they've somehow lost the ability to suspend disbelief. Geez Louise.