Quoting skwey:" wow really? maybe it's a religious thing with her then. lol she was part of the "boarding school" era ... [snip!] ... when our tribe was all split up and forced into boarding schools. the one she was placed in was a Catholic one and run by nuns."
You are native american I assume? I think it goes back to a time when bathing was not done often, so you saved money by doing it less, and when you did do it all the kids plopped into the tub together. From what my nana told me *she's 93* that it was pretty common to share bathes until you began to change *her concept of puberty*, and even then not always. As society gets more advanced,we get more used to the concept of privacy things like this being to be an issue. Anyway going back to the OP, I would just let them make the choice. When kid's want to be modest they are going to let you know.