I think it's a great book, because it shows something that kids, like my four-year-old, would totally do. When he had a new pair of shoes, he walked into preschool telling everybody about them, even though we got there late and the teacher was talking to the other kids. He can't hold his enthusiasm inside, and that's an extremely common thing for kids. They have to learn respect for other people and their time, especially when others are trying to learn in a group context.
Message
Making a mistake is not permanent. You can fix things that you did wrong. Or, when you're at school, you need to let the teacher talk without distracting the other children.