Depends what she’s into reading…..but….
Sabrina Fludde by Pauline Fisk
I Capture the Castle by Dodie Smith
Books By:
Charles deLint
(for Fantasy/modern mythology) Especially- Yarrow, Angel of Darkness, or Svaha
Toni Morrison
(for ‘modern classics’) Especially- Bluest Eye, Sula, or Beloved
Garth Nix
(if she’s not already gone there, but while the characters are really well written they are a bit childish (but depends if she’s reading DWynneJones as they are similar to her)
Virginia Woolf
(More modern classics, but slightly older) Mrs. Dalloway, The Waves, Orlando. If you do Mrs. Dalloway I would really encourage you to also get Micheal Cunningham’s The Hours as they are related (but the latter is more modern you might remember there was a movie not long ago) and it’s especially good too.
I could go on…