What time do you think a 15 year old should go to bed on a school night?

On a skl day i wake up at 5:45 and go to bed between 11 - 11:30. I admit that i do feel a bit tired through the day but i'm just wondering what time other people round my age go to sleep cos i think going to bed at about 9 or 10 is too early. What do other people think??