Hi Joseph

If it were my daughter, I would have her carry her own school backpack. That way she has something that she is used to carrying, and will hold a fair amount of stuff. I wouldn't worry so much about the camelback.

But a word of advice! Check our her backpack first, to make sure she doesn't have a ton of extra stuff in it from when she takes it to school. Six "my little ponies" and all their gear adds some unnecessary weight to her pack!