SOLVED. Fantasy? girl goes to alternate world and meets another girl and must save world from dying? find something lost? both look different when meet in reality. [s]

[Kaitlyn]

a girl goes to her grandmother's house (family issues?) and goes into a greenhouse, which somehow takes her to a fantasy world where she looks different and meets someone who is also there somehow. they come across mermaids who try to drown them (turns out they are able to breath under water) and some elves who give them pretty clothes made of plants (?), near the end they have to stop the world from dying and get past a banshee and maybe a raven (idk about that for sure) and there might be somehting magical like a shell or seed? rock? read it when i was like 9 on my ereader, like 5 years ago? for some reason i think the title is something like fairy godmother diaries, but i might be wrong.

[Mai]

I found this book through a Google search. I haven't read it so I don't know if all your details match but it looks like it could be the book you are looking for:
Birdie's Book by Jan Bozarth (The Fairy Godmother Academy #1)
When Birdie goes to visit her grandmother for the first time, she learns that her grandmother is a fairy godmother—which means Birdie's a fairy godmother too! Trained by fairies in a magical land called Aventurine, human fairy godmothers have been hidden protectors of the world for centuries. Birdie' s family talisman, a singing stone, has been broken, and now only Birdie can use the stone to travel to Aventurine to repair it.
When she gets there she meets Kerka, a warrior-like girl who has been sent to help her find the other half of the stone. Will Birdie and Kerka have the knowledge and strength to banish the shadow that has come over both the garden in Aventurine and Birdie's family? One thing's for sure—no one who travels to Aventurine will ever be the same again!

[Kaitlyn]

Mai wrote: "I found this book through a Google search. I haven't read it so I don't know if all your details match but it looks like it could be the book you are looking for:
Birdie's Book by [a..."
That's it! Thanks so much!!!