It sounds as if they gave you a ticket (not a misdemeanor). If it is a misdemeanor you would need to be formally charged by the District Attorney's office. If you want/need to make sure it doesn't show up on your record, you should get an attorney before you go forward.
I agree with Attorney Dommershausen. It appears to me that you have been given a citation for theft. A citation is different than being charged with a misdemeanor in the same way that a speeding ticket is different than being charged with a crime. A citation can result in money penalties, but you cannot go to jail. A crime - such as a misdemeanor or felony - can result in both money penalties or incarceration in jail or prison. It is a big difference.
As for showing up on your record, that depends on what record you mean. Receiving a citation does not earn you what is generally referred to as a criminal record. You do not have to say you ever were arrested or that you have ever been convicted of a crime for job applications or school applications. Anyone doing a background check will see that you have never been convicted of a crime. In that way, it will not be on your record.
Some municipal and campus citations do show up on CCAP (http://wcca.wicourts.gov/index.xsl) for a period of 5 years. In that respect, it could be visible to someone who cared enough to look you up, but it would only show a citation and not a crime, if it even showed up there at all. If you were already given the ticket, you should be able to check that site right now to see if it shows up.
The citation may also show up on your permanent record, available only to law enforcement agencies and attorneys. Any speeding ticket you ever get is on there, too. It is the full record of all recorded interactions you have with law enforcement from all states. It is not something that the public has access to, and not something I would be terribly concerned about where I you.
If the campus police are handling the offense, they may not be handing a referral to the local authorities. Since you were not intending to permanently deprive the university of their property (an element of theft), you may want to hire an attorney to try to negotiate for a lower fine. You have to balance the cost of an attorney with the savings you may realize from an attorney's services.
I wish you the best of luck on your case.