Does anyone know any good books on the field of Physics, particularly astronomy/cosmology, etc.?

I'm a twelve year old girl and I've recently become infatuated with the many fields of Physics, most particularly astronomy. The problem is, most of the books I try to read are off limits to me because of my age (such as Michio Kaku's Physics of the Impossible). Although I intend to buy this book (and others) in the near future, are there any other books you could recommend?