Simple Assault Consumated with Battery

I was charged last week with simple assault consumated with battery on an Army Post in Virginia. One of my co-workers said that "I grabbed her body and gave her an unwanted kiss upon her lips" in the parking lot after work. There were no witnesses. There were 4 witnesses that I was at my desk inside working at the time of the incident.
Is this really simple assault consumated by battery? I am having a hard time believing it. The co-worker waited 6 weeks to report the incident. Does that have any bearing on the case?
I have to appear before a Federal Magistrate next month. I have a spotless record.
I assume that she has no witnesses and I have 4 alibis, this should not be a hard case to win. Naturally I am nervous. If for some reason I am convicted, what do you think the penalities would be? The JAG filed charges after they got her statement and I declined to offer a statement at the first interview. JAG thought that was enough evidence to file charges. The MPs will not interview any witnesses in our office, people who could clear me.

Is this question in relation to an upcoming an Article 32 Hearing? Or have you been charged in a civilian court?

I am retired military, now a GS civilian and being tried as a civilian.

If you know the statute under which you are charged, it will be possible to point you to the exact language and penalties. It is probably a charge which carries a penalty of up to six months of incarceration.

You should consult a criminal defense lawyer or, if eligible, try to get representation through the Federal Defender's Office.

You may wish to think about not only who might be able to prove that this didn't happen, but also why this person would make up the accusation. Which is to say, if a jury understands both, the chances of acquittal go up significantly.

Thanks for all the advice so far.
I have talked to an Attorney, at my own expense.
I am concerned that the Military Police did not investigate the incident and that JAG went and charged me based on her statement. There are several witnesses in the office that saw her leave and me still at my desk. The MPs don't seem to care.
I have to appear before a Federal Magistrate on 12 June. Is it worth bringing this up then?

It's an arraignment? Bringing up your defenses would seem premature.

Yes it's the arraingment. I am trying to stop this from going to trial, if that's possible. Probably not.