Should school shootings be considered self defense?

If a school covers up a vicious beating you received from the jocks its obvious that they have little to no concern for your safety and the popular kids aren't helping you out either.Many school shooters said the people they shot were out to get them.If you have reason to believe that someone is out to get you and you know that no one is going to stop him shouldn't that give you the right to get them before they get you?