This girl spends her summer with her childhood best friend (whom she hasn't seen in some time) because her parents are in the middle of their divorce. Her friend then falls for a lifeguard and convinces the girl to go on a double date with them and the lifeguard's cousin. The cousin is kinda rude to the girl because he didn't want to go on the double date but later they become friends and go roller skating at one point and develop feelings for each other. Then there's some drama because the lifeguard is a cheater and the cousin didn't tell the girl so she couldn't warn her friend. I don't remember much more except that they go to a beach party at one point. I read this cute story as a teenager and I've been racking my brain for weeks now but I can't remember the title, please help.