SOLVED. Fiction: High schoolers become obsessed with an author who then writes about them?

[Ali]

I can't remember the name of a book I read sometime in the last five years. It's about an author who becomes friends with a group of high schoolers, and then writes her next novel about their secrets. I think it had the word lying/liar in the title.

[Ali]

found it - all of this is true by Lygia Day Peñaflor.

[Rainbowheart]

Glad you found it!

All of This Is True for the link.