In Maine this is not rape or Gross Sexual Assault.
My response to your question is a generic response and should not be construed as controlling to your case. I can not effectively advise about your case without knowing all the facts. Additionally, my response does not create an attorney-client relationship. You can contact my office to schedule an appointment if you would like to have me represent you.
Kissing alone without anything more wouldn't be rape but there can be other offenses charged. If this happened four years ago I don't suppose you have much to be concerned with but if the police do contact you do not say ANYTHING to them without an attorney.