I can understand this is a frustrating situation for you. I would think jail time would be a harsh penalty for a first offence as well, but there are many factors that may influence a judge's decision. Any additional information you could post about what happened may help you get better responses from other posters.
I suggest you speak to an attorney regarding legal options for defending against any criminal charges. You can find more information about an attorney through the attorney locator service on LawInfo's home page at:
http://www.lawinfo.com/. Some do offer free consultations.