Legal Question in Criminal Law in California

Sexual battery under Penal Code �243.4 is a "wobbler," meaning it can be charged as either a misdemeanor or a felony, so the felony statute of limitations of three years would apply.

(If you were under 18, a different statute of limitations would not apply.)

An individual cannot "press charges." Only the District Attorney can initiate a criminal prosecution.

You would have to contact law enforcement or the District Attorney in the jurisdiction where the offense occurred. An investigator will take a report and forward it to the DA, who will decide whether to file charges.

The perpetrator cannot be convicted based on things your friends told you. That is considered hearsay. In order to proceed with a trial in a case where you have no personal knowledge of what happened, your friends who actually witnessed the events would have to testify.