I agree with PP’s that you should get her a collection of Poe short-stories. I read one when I was about her age, and I remember my favorite was “The Pit and the Pendulum.”
Others you might try:
Agatha Christie
Interworld by Neil Gaiman
The Green Knowe series by Lucy M. Boston
The Dark is Rising series by Susan Cooper
Lord of the Flies
1984
maybe Bradbury? but I don’t know if there’d be any content problems.
Hitchcock had some great anthologies for kids. I think they're out of print, but you can still get some on Amazon.
https://www.librarything....ng+Readers
She might also like non-fiction about unexplained phenomena like the Bermuda Triangle or the Loch-Ness Monster.