If I got a desk ticket for shoplifting, what can I expect?

If you are a first-time offender, then you may be given what is known as an "adjournment in contemplation of dimissal" (ACD). This is a legal tool which allows for the postponement of a criminal case so long as the accused fulfills certain conditions; if they do then all charges are dismissed. The conditions typically include that the accussed stay out of trouble during the postponement period, perform community service, make restitution to the victim, and complete a shoplifting awareness class and/or an anti-drug program.
An ACD is not probation or a conviction. The person receiving the ACD will not be asked to admit any wrongdoing. For an ACD to be granted, the judge, prosecutor and the accused must agree to it. Once the imposed conditions are met then at the end of the adjournment period the charges are dismissed and the accussed's record is sealed; there is no rap sheet or criminal record. That having been said, it is common practice for local law enforcement to keep a record of the arrest, although access to it is not allowed without an unsealing order which must be issued by a judge.
That having been said, an experienced criminal law attorney may be able to get the charge dismissed, eliminating the need for ACD. At this point, you should consult directly wirh a local lawyer who handles these type of cases. They can best advise you further.