Bedroom ideas?

Sabine

Hey ladies! Teen girl here, kind of geeky, loves horses and reading. :D I'm redoing my tiny bedroom, but I'm not allowed to change the walls (honey colored wallpaper that's been there since I was a baby) and one of the walls is on a slant. Also, all my windows really low on the wall, like their tops are a little above my waist. Do you have any decorating ideas? I need inspiration (And please, not too much pink, I'm not a girly girl by any means)!