Off Campus by Caroline Says

Back for her second year, Nikki Olivetti feels like she's finally finding her way at Wellington. And she's ready to show someone else the ropes, someone new, someone like Delia Breton, a transfer student from California with a dark past. Though Delia doesn't quite fit in anywhere, she knows how to have a good time everywhere.

But when the hunt for fun takes Nikki and Delia off campus, they find themselves in serious trouble. Even if they make it back, they might have forever ruined their chances of graduating to the upper class.