I'm 33 and I'd still sleep for 2 hours in the afternoon given half a chance and I'd still go to be at 7.30pm if someone took care of everything else .
Seriously, I was a sleepy 4yr old and still napped up til I started school (ages with your DD) and went to bed about the same time.
My mum says I would come out of school and just lie on the couch for a while watching any old thing on the telly to recharge.