You don't need a rare disorder to be afraid of junior high school students.
Pedophobia, a real disorder involving an extreme fear of young children, is preferable to pedophilia in almost every circumstance. Including this one. Of course, pedophobia isn’t so great either if you’re a teacher in a junior high school. It might be brave, but we feel like choosing to become a teacher despite your known fear of children is like becoming a doctor despite your fear of stethoscopes or becoming a veterinarian despite your fear of people who like cats.