Summer Girls by Jennifer Dugan

Cass has a rule about dating summer girls - just say no. Every year the idyllic beach town Cass's working-class family calls home is flooded with summer girls, the obnoxious daughters of the rich, who stay in their families' summer homes, sail their yachts, and generally make things unbearable for townies like Cass. Birdie is the ultimate summer girl. She’s the daughter of a wealthy real estate developer dad and a social media influencer mom, and this summer Birdie happens to be in big trouble for accidentally crashing her boyfriend's very expensive car. As punishment, Birdie must spend the summer with her father at the beach - but it won't be a vacation. He's enlisted the help of Cass, whose dad works for him, to keep Birdie on the straight and narrow, including getting her a job as a beach parking lot attendant. As the summer heats up, Cass realizes some rules are made to be broken, and Birdie just might be different from other summer girls. This book is available in paperback.