I am a 16-year old highschooler, and a certain student has been constantly harassing students, physically, verbally, and mostly sexaully.
there have been attempts to tell the school administration, but the school has a reputation for letting special-needs students get away with anything, and thus my school has taken no action.
I'd like to contact a prosecutor for his countless offenses because I want to make my school a safer place.
A student can complain about harassment by another student to various school officials, to police and to a prosecuting attorney. Whether any of those people take any action as a result of the complaint would be, of course, up to them. If you are the target, you may also consider self-defense training.
You can make a report to the police but there is no guarantee they are going to pursue the matter.
You wouldn't be pressing charges. That is a decision made by a prosecutor. You could certainly contact law enforcement about your concerns and things would go from there.