I grew up with two older sisters, and no-one had any issues with seeing anyone else naked. Anyone could and would use the toilet or basin whils someone else was in the bath or shower.
The present Mrs Hughes has a rather shyer approach, but we are perfectly comfortable being nude around each other – have been since we started going out (not that we go out nude!)
I tended to keep myself private when the girls were growing up, but I did all the baths until they were about nine, then I taught them to wash their hair and bathe properly, and haven’t seen them nude since.
My granddaughter is now well past the age of being bathed, and the boys are still pretty much OK about being nude when they share baths at ours.