Well, I think all children are different. When is first grade? Is that age 4/5? We call that reception...or Year One is the year after. My son used to go to bed at 8.30, and then get up at 7.30, so got 11 hours sleep. Though that it is later than many parents I know, whose children were in bed by 7 - some of them got up at 6 am, though, so it's all swings and roundabouts. If she has only just started school, it may just be that the day exhausts her. Many children find it hard. Even if she has been in nursery, the day is more mentally tiring at school, I think.