It Ends with Us question

hello i wanted to know if anyone recognizes the premise of this book and if you could tell me the title! the book is about this highschool (?) aged girl who can see ghosts, and its her job to help them with their unfinished business so they can move on to the afterlife. in this book she ends up seeing the ghost of the older sister of the mean girl at her school (who shes also in a tutoring program with where they tutor elementary aged kids). The ghost sister doesn’t remember exactly how she died, only that she fell off a balcony, so the girl who can see ghosts has to try to befriend the mean girl so that she can learn more about her dead sister. she (the girl who can see ghosts) ends up being invited over to the mean girls house and she asks to use the restroom and starts exploring the mean girls house trying to find her sisters room, which DOES have a balcony, but the dead sister confirms that she didn’t die here (also the sisters mom has sort of renovated her dead daughters room to be an at home gym for some reason??) anyways the girl who can see ghosts is eventually caught snooping in the dead sisters old room by the mean girl and is kicked out of the house but she does help the dead sister move on in the end (i forgot how though). if any of you know this book please let me know or reply to the post because i think about this book so much and its driving me insane that i can’t remember the title. It might’ve been a YA book, but i’m not 100% sure. Please help omg i’m going crazy 😭