A recent one I really enjoyed (I was actually surprised) was Entwined by Heather Dixon. It’s a really good retelling of the 12 Dancing Princesses.
Girls are spunky, plot moves pretty quickly, and the dark/sad moments are pretty quickly glossed over. Reminded me very strongly of the Blue Sword/Hero and the Crown books.
There are some courtships and marriage plans, but most of them are logically discussed or lampooned by the multiple younger sisters who think the whole idea is quite silly. There’s not much mooning about that I recall.
If she’s up for sci-fi, there’s a really slim YA novel called A Beautiful Friendship by David Weber that has a girl making contact with an alien species that are essentially super-smart 6-legged cats. Very quick read, no romance, no really dark material. There are some very well-written short stories following up on various people’s interactions with the cats throughout the timeline of that universe if she’s interested in the concept.
Another good one is the Graveyard Book by Neil Gaiman. A very well-done send off of the Jungle Book.
If she’s open to historical fiction, I’d recommend Catherine, Called Birdy, by Karen Cushman. Really funny, diary-style writings of a 14 year old medieval noble girl.
What else… Princesses… Ella Enchanted, Princess Academy, Beauty (by Robin McKinley - I would wait on Rose Daughter, but Beauty is spunky and nicely paced). The Ordinary Princess, by M M Kaye, Bella at Midnight, by Diane Stanley (very good and inventive reworking of Cinderella) Tuesdays at the Castle, by Jessica George (castle gets new rooms on tuesdays, princess has to save king and queen - very quick read and quick resolution)
Tiny people: the Borrowers (ad infinitum sequels) by Mary Norton, the Littles (very junior, but you could probably finish a book in two nights for something fun and non-challenging) by John Peterson, Terry Pratchet’s Truckers, Diggers, and Wings (perhaps not for everyone) and also his unrelated The Carpet People, The Indian in the Cupboard, Mrs Frisby and the Rats of NIMH (and sequel).
Mystical: Have you considered A Wrinkle in Time yet? Very nice series also. The Neverending Story (much better book than movie), the Invention of Hugo Cabret (needs to be looked at to enjoy) The Phantom Tollbooth, The Egypt Game by Zilpha Snyder.
Girl power: A Tale of Two Castles, Gail Carson Levine (girl meets a dragon and giants and solves a mystery), Dealing with Dragons (et al) by Patricia C. Wrede (really hysterically funny set about a princess who runs away to get stolen by dragons because she doesn’t want to be a proper princess and get rescued and live a boring life. Very funny, very girl-powered. Ronia the Robber’s Daughter (by the writer of Pippi Longstocking - lots of fun, and a really spunky girl lead)
Have you considered any of Tamora Pierce’s books? The Alanna series is a girl pretending to be a boy so that she can be a knight (all she ever wanted in life) the Immortals series has an interesting girl who can talk to animals and learns she’s related to the Gods, Beka Cooper is about a girl who trains to be a medieval police officer, and Tricksters series is the daughter of Alanna who goes into politics on a Japanese-style island.
Those are all in the same universe, pretty good to start with at this age (each series has the girls starting around 10 or so, but they do age up to around 16 or so over each series, and there are talks of childbirth and homosexuality and birth control eventually.
There’s another set - the Circle (two sets of 4 books) that are in another world, and set a bit younger. It’s about a cluster of kids from unfortunate backgrounds who have to work together and learn discipline to control their magic and become helpful to their world.
That’s all I can think of off the top of my head… 