How about pleading NOT GUILTY. Never plead other than not guilty unless you have legal counsel as to the implications of doing otherwise.
Almost all medical schools will run a background check on you. You can count on them finding out your criminal record.
Blaming your moral turpitude on an eating disorder also doesn't bode well for you becoming a doctor. Nobody wants the mentally ill in charge of patient care.
NEVER take advice from the police. They don't know what medical school and your eventual medical licensing requirements are going to be.
You should be VERY scared. Get your butt to an attorney. The best thing that can happen for you is to get into some pretrial intervention that can avoid the conviction entirely.
By the way your title "civil misdemeanor" is nonsense. First, you are not being dealt with as a civil case. You may expect to also get a letter from the store's "lawyers" demanding civil restitution, but if you have a court date, you are being CRIMINALLY charged. New Jersey doesn't have felonies or misdemeanors officially, just crimes and disorderly person's offense. Note that this makes little difference to you. You being convicted of a disorderly person's offense WILL RESULT IN A CRIMINAL RECORD.

