When children are thinking about what they want to be when they grow, they really don’t know enough about the jobs that are out there in the real world. They just think they know what doctors, lawyers and nurses do every day, but they really don’t. It isn’t until later when they start communicating with these people and learning about their jobs that they start to understand the tasks of the careers.
Even in college, students will change their major to become something else. As a matter of fact, college students change their major frequently, so it would be unusual that someone became what they wanted to be when they were a child. For me, I wanted to be a nurse and then became a teacher.