What age would/did you let your kids shower by themselves?

I’m coming here because I think this is the right place to go. But my sister is 9. My parents are divorced and my mom let’s my sister shower alone with the curtains closed, I think the doors unlocked just incase she slips or something. But my dad on the other hand has the door glass door taken off the shower, watches, and helps my sister bathe. She said she doesn’t mind it and likes him watching...to me it’s really creepy and I don’t know what to think about the situation. I don’t live with either of them but it just seems weird to me. Should I be worried? What age did you guys or would you let your kid shower alone? via /r/Parenting https://ift.tt/2Q2ZXSI