The maximum penalty you face is 60 days in county jail and a $500.00 fine. However, based on your lack of prior record, it is unlikely you would get sentenced to the maximum penalty. Assuming the State can prove the charge (can anyone place you behind the wheel???), your goal would be for the court to withhold adjudication of guilt, so you are not convicted of the charge and order you to pay a fine and or court costs.
Since this is a first charge, make sure you hire an attorney to review the case, as sometimes the alleged victims are not willing to come to court IF your insurance has already paid for their damages. Your attorney may be able to get this charge reduced to a civil infraction (thus, no criminal record!). As a first offender, you may also qualify for a diversion program that would keep this criminal case off your record. There's no need to have a criminal record over something like this. Also, there are plenty of defenses to leaving the scene of an accident. Get an attorney (did I mention that already?).
These charges are often tough for the State to prove. Often times the only witness listed is the officer who did not observe the accident. A good attorney will prevent his testimony. Also, sometimes the witness has already received restitution, is out of the area, has a bad address, or can not identify you. I would not worry about the penalties as much as if the state can prove their case.