Marvin,

If you were to confess to your conduct, it's unlikely that you would be criminally prosecuted. Although what you did is a serious crime, you were a minor at the time, the victim seemingly has no knowledge of what you did, and the only evidence would be your uncorroborated confession. It is unlikely that a prosecutor would choose to take such a case to court.

But if you admit to this conduct, you can reasonably expect to be subjected to an in-depth interrogation about it. You'll be asked the full name and current whereabouts of the victim, and full details about each instance of touching.

You should not call the agency and come clean. Nor should you come clean at the day of your polygraph. If you confess 1) you'll be permanently disqualified from employment with any federal agency with a polygraph screening requirement; 2) you'll fail the polygraph (if they even bother to proceed with it); and 3) your confession will be shared with any other federal agency with which you may seek employment in the future and will likely disqualify you.

If your conscience troubles you, and you feel the need to confess, you'd be better off withdrawing your application and confiding in a trusted friend rather than a federal agent who will be taking notes. On the other hand, if you sincerely regret your past conduct, have matured since then, and would never do such a thing again, and still wish to proceed in the hiring process, then it would behoove you to keep your mouth shut and educate yourself about the polygraph. The Lie Behind the Lie Detector, which you can download from this site, would be a good place to start.

The original post has been deleted at the poster's request.