What path do you need to take in order to be a successful school nurse ?

You would want to go through the same nursing education as any other type of nurse. I would recommend that after you finish school and pass the board exam, that you work in a hospital for a year or two. This gives you the chance to see many different types of patients while becoming comfortable with your own abilities. You will be a much better prepared school nurse if you have seen and done a lot going into it. Many schools have children with disabilities, medication that need to be given, physical needs, and close monitoring, and having dealt with these things before will make you much more prepared for what you might find at a school, where typically, it would just be one nurse on. I would recommend seeing if any school nurses in your area would allow you to shadow for a day to see what a typical day is like.