Just thinking of how I got all my kids off to bed at a good time for everybody to stay in good moods. It was really hard. But, because you only have 1 daughter the easiest way to know when to send her to bed would be according to waht day it is , whether she has school etc. A girl of that age needs 10 nours a night sleep. If she goes to bed at 9, she should be up by 7...