If you're accused of sexual harassment or sexual misconduct by a fellow student or in any capacity at a college or university, you should not speak to the school or anyone else for that matter without taking the necessary precautions. You should let your parents know. You cannot depend on the school to do the right thing, the campus police to do the right thing, or whomever else may be involved. You shouldn't talk to your friends or classmate initially until the proper precautions can be taken.
It is an incredibly serious allegation and the potential consequences can be severe if the matter is not handled properly. Having an experienced attorney advisor can help you best understand and navigate the process and can help you best respond to the allegations. They should be involved from as early as possible in the case.