My kids NEED their sleep or they become the walking dead....true zombies!!!
I say if it aint broke, dont fix it. Who cares what other kids do. This is your DD. Studies have shown that todays youth is under nourished in many ways, not just food value, but they are sleep deprived too!
We have an 8-8:30 bedtime here but my DD is only 9. We use the 9pm extension as a reward. If there is something on TV we might allow them to stay up that bit extra to watch. Like on sunday night we watch extreme home makeover as a family unit because it brings charity and humanity into our home and a tool for us to show our children the other side of the coin, so to speak.
Anyways, just my two cents! I want my kids to have optimum brain power and adequate sleep is just a part of that equation.