That Summer by Sarah Dessen
Haven is 15 years old and having a terrible summer: her father is getting remarried, her best friend is away at camp, her older sister is marrying a guy that Haven doesn't really like, and Haven is almost six feet tall and still growing. She looks back to one summer a few years ago when things were still perfect, when her sister was dating the gregarious Sumner Lee and her parents weren't divorced yet. When Sumner appears back in her life, Haven believes it's a sign that things will get better. Will they?
This is the first book I've read by Sarah Dessen, and it's also the first novel she had published. I found Haven to be a very believable character, from her interactions with her sister to her perceptions of her minimum-wage job. I especially enjoyed (and related to) her outburst at the sidewalk sale at the mall when a cranky customer showed up; Haven did what we all want to do in situations like that, whether it's the right decision or not.
3.5 stars out of 5 for That Summer.