In this joyful and impactful picture book, a transgender boy prepares for the first day of school and introduces himself to his family and friends for the first time. Calvin has always been a boy, even if the world sees him as a girl. He knows who he is in his heart and in his mind but he hasn't yet told his family. Finally, he can wait no longer: "I'm not a girl," he tells his family. "I'm a boy--a boy in my heart and in my brain." Quick to support him, his loving family takes Calvin shopping for the swim trunks he's always wanted and back-to-school clothes and a new haircut that helps him look and feel like the boy he's always known himself to be. As the first day of school approaches, he's nervous and the "what-ifs" gather up inside him. But as his friends and teachers rally around him and he tells them his name, all his "what-ifs" begin to melt away. Inspired by the authors' own transgender child and accompanied by warm and triumphant illustrations, this authentic and personal text promotes kindness and empathy, offering a poignant and inclusive back-to-school message: all should feel safe, respected, and welcomed.