Halpin, Brendan. Tessa Masterson will Go to Prom. Walker Childrens, 2013.
I don't want to spoil the rest of the story, so I'll stop my summary there. This book was fun and funny and adorable and had a great Jordan Sonnenblick-esque ending and I was hesitant to start another book afterward, thinking that nothing could top the amazingness I'd just read. And maybe it can't.
If you haven't read this book yet, you need to. Even if it bothers you that one of the main characters wants to go to Purdue. After all, he's just a character. :)