My son is 8 and my daughter is 6,..they wander in and out of the bathroom and bedroom as they please regardless if I am in the bath, shower or dressing.
They are of an age that I don't bath them but they are comfortable seeing me naked and will no break off mid sentance if they barge in when I'm naked asking a question.
There is nothing sexual about it in the slightest.
I am their mum, mum is naked, big fat hairy deal, answer the question mum.
They don't bat an eyelid.