Teen horror fiction book about a “babysitter”

So, the main character was a teenage girl whose name I believe was Zoe or something along that, she was writing letters to a camp or a project she wanted to be part of, these were babysitting stories, she had a story about a pair of twins, a boy that was obsessed with food, a girl that loved the Jonas brothers so much she got a private concert in her backyard but ended up being electrocuted etc, at the end of the book, her mom reveals all of the stories are lies she made up so that she would be interesting enough for the camp.

I’ve been searching for this for a while, I’m not crazy, this was my favorite book until my grandma threw it out by accident, I remember the title being something like lies but I’m not really sure about that