It starts out being written like the MC's a latchkey kid: she gets herself up and prepared for school in the mornings, makes her own food (or has it prepared for her, so she just has to reheat it/take it to school), the house always seems to be empty except for her. Maybe there are occasional notes to her. But eventually it becomes apparent that she isn't living with any adult--maybe with a ghost (not, I think, a family member)? While she's on the verge of sleep she could her it then, and give further evidence to the "not squatting in the house" misleading. Not as the main plot, because she knows about her circumstances so it's not a mystery, but as an around-the-edges thing: she goes off every day having her adventure, and comes home to this empty house and loving notes. Maybe it affects how she acts, like she absolutely insists on being home by a certain time, and the reader is very confused about why until she comes home late one day and the walls are bleeding or something.

Hm, might be fun to do it as a coming of age thing, and/or if she gradually realized that their relationship was abusive and successfully managed to get the ghost to change.