Falling In My Own Gravity (Bill X Reader X Dipper)

A new girl in Gravity Falls, 12 years old with a fire in her eyes.
Showed up on a bus one day, no family, no story, just a strange notebook and a backpack.
She seems to know more than she lets on, hiding in the woods, always being at the right place at the right time.
The girl's name, Is (YN) (LN).