If you were sentenced to any custody, it could range anywhere from the time already served up to one year in custody. Bottom line, it is possible that you might do no custody at all. Realistically, there is no way to know for sure until the time that you are sentenced....which is how the courts prefer it.
You should plead not guilty and either hire an atty or request a court appointed attorney if you can't hire one. Feel free to call me and we can discuss. Wilson Brott. 231-938-1000
Your first court hearing should be a pretrial conference. The prosecutor is likely to offer you a deal in exchange for a guilty plea. If you wanted to plead guilty you can request that the prosecutor give you a No Jail Recommendation in return for your guilty plea. This would limit you to fines and costs for the crime.
If you do not want to plead guilty to the offense, you should hire an attorney, or if you cannot afford one, you can ask for a court appointed attorney to assist you in the matter.
If you have no prior criminal history, you may be eligible for a first offender program which would allow you to keep this off your record. You can talk with the prosecutor about that possibility. If you were over 17 and under 21 at the time of the crime, you are eligible for HYTA (Holmes Youthful Trainee Act). This statute is directed at youthful offenders who have exercise poor judgement and find themselves in a situation such as the one you describe. Like a first offender program, HYTA would allow you to complete a probationary period without a conviction being entered. If you complete the probation successfully, the conviction is not entered into your public record.
The judge would decide whether or not to grant you HYTA status, though the prosecutor can object. For a first offender program, the prosecutor would have to agree.
You should have an attorney to explore the options available to you. This first hearing will just be a pretrial--you don't have to decide exactly how to resolve the case at the first hearing.
Best wishes to you.