"Here or were you came from? Do you usually offer to help random strangers."

Most likely it's something the girl decided was something she was supposed to do. After all, she looks very young and, at that age, the main thing kids are supposed to worry about are schoolwork. Not, Kira admits to herself, that it always works out that way. But aside from the unusual clothes, easily explained by the situation they find themselves in, there's no reason to suspect the girl had a very unusual life.