I'd second the "Jane Eyre" recommendation, possibly "Gone With the Wind" and absolutely "To Kill a Mockingbird" - if she hasn't already read those. My mother wouldn't let me read "The Grapes of Wrath" at that age; I don't know exactly why since I'd read some other things by then that weren't any more sexually explicit.
I also recommend Ngaio Marsh - her writing is very good and so are the mysteries. Dorothy Sayers is another mystery writer of about the same ere, along with Agatha Christie. Dorothy Gilman writes some very entertaining mysteries with Mrs. Pollifax (a Miss Marple sort of older worman but with a more physical take on her activities) which go to other countries and therefore include some cultural info that is interesting.
I read lots of mysteries....a good writer can teach lots in such a story and make it fun to learn!



What sane person could live in this world and not be crazy? -Ursula K. Le Guin, author (1929- )