You need to plead not guilty and request time to hire a lawyer.
I would recommend that you find a lawyer from this forum in your town and interviewed two or three to assist you with your case.
If you have no prior record you may be eligible for a diversion program meaning you could get your case dismissed.
Your record is too important.
You should plead Not Guilty, and then request time to hire an attorney. If you cannot afford an attorney you may be able to have one appointed to you by the court. These types of cases rely heavily on testimony and or statements from the other party. You definitely need to speak with an attorney to discuss your case, and figure out what your options are.