The majority of the book is actually hilariously funny. Helped along by the irreverent behavior of Rob's grandfather and Rob's own snarky observations about his school and family, this breezy read (I finished the entire 300-page book in an afternoon) is good fun. I would have been happy to have it end like that, but the author takes it in an entirely different direction that to me felt tortured. If you go back and re-read carefully there is some foreshadowing for the ending but it really doesn't have to be present (see below if you don't mind spoilers). And the book's final chapter, where the fourth wall is dropped altogether, really just seemed like nonsense to me.
<Spoiler> There will be readers who will feel it is really important to the story that Rob is trans, but honestly I found no value in that reveal except to give this book a new audience and an additional agenda it didn't need. There's very little in this story that relies upon Rob's gender identity or birth sex. Without it, this is a good story about a boy named Rob who had a grandfather who helped him find himself. And at the end of the day, it doesn't matter that Rob was once named Roberta.</Spoiler>