Minors have limited rights anyway, but mostly in the voting side of things. An adult is defined as someone who has reached the “age of majority”. After that, they are free to make adult decisions and be fully accountable for their actions.
Schools are basically forced to accept responsibility for kids for a number of hours per day. As such, schools must create a safe environment for all students and maintain some kind of order and ensure the rights of other kids aren’t infringed.
Me exercising my rights can never infringe on the rights of others. Many people don’t understand that.