Conversed: "So the girl's really in the regular cast. I wonder how she will affect them?"
A child on the team could cause problems: Alice could be a whiny Spoiled Brat, or what if her parents don't approve of her being taken on an epic journey at such a young age? And what about school? Alice's future depends on it, after all...right?
The teenage heroes have no idea how to deal with a kid. Things are much messier with Alice living with them.
The journey isn't fun at all. Tragic incidents like watching her Big Brother Mentor slain in battle, or even an entire Break the Cutie story arc, can't be good for her. The Hero tries his best to keep her positive outlook or even her sanity when things go really bad.