Sleep time for a 13 year old girl?

it depends on the parents. how late they will allow their kids to stay up is up to them. a 13 year old can go to bed before the time they are supposed to go to bed. any kid can. an average person needs maximum 8 hours of sleep to freshen up the body. you can always sleep more but its up to your body on how much longer or shorter than 8 hours of sleep you get.