Messy Perfect, by Tanya Boteju

Years ago, Cassie and her best friend Ben got caught dressing up in each other's clothes.  It wasn't so bad for Cassie to be seen in Ben's trousers, but Ben wearing her skirt took some more effort.  But rather than explain the truth when the rumors began to fly, Cassie abandoned Ben to bullying homophobia.  A few weeks later, Ben left the school.

Now, he's back. Wracked by guilt for her childhood cowardice, Cassie is determined to make things right and she alights on the idea of setting up a Gay Straight Alliance in her very conservative Catholic school.  Allying with an existing GSA at a nearby public school, Cassie starts a secret campaign of "pop ups" to make her school more gay friendly (and thus easier for Ben).  But as the project consumes more and more of her time, Cassie's grades start to suffer and her relationships with her friends and family begin to fray.

As for her goal to fix the mistakes of her past, it doesn't quite work out as she planned.  Ben is amused, but strangely non-committal to the project and Cassie begins to realize that making her school more accepting to queer students may be more important to her personally than she's comfortable admitting.

Cassie is a perfectionist who makes plenty of messy mistakes along the way in this story but does a decent job of knowing how to fix those errors and come back better -- a mash-up that gives the book its title.  While the novel can be boringly repetitive and overly preachy about the importance of safe spaces, Cassie's journey into self-discovery is compelling.  I liked her and also the many supporting characters as well -- a colorful cast of peers who represent an exuberant form of teen queerdom that has fallen out of fashion in YA lit shockingly quickly in the wake of terrorized libraries.  Far more so, I appreciated a strong presence of adults in this story, ranging from the keen librarian to the surprisingly sympathetic principal to a mother who was confident enough to know when to crack down and when to let up.