Concluded that even with such well-behaved girls, a large group would mean they would send more adults. Especially given there is a risk of danger. They are not modern, they expect the girls to be able to cope with some situations, especially given they have magical abilities to add in escape, and they do not expect much danger. And while the heroine is older than the rest, they didn't plan on her helping.
So, probably only a dozen. Which means that the heroine ought to know all their names.