Definition - What does First Offense mean?
A first offense is a person's first criminal violation of the law. A first offense can be any number of different criminal violations. For example, it could be petty theft of $50, or it could be grand theft of $10,000.
All that is necessary for something to constitute as a first offense is that it is the first time that an individual has been charged with a crime.
Justipedia explains First Offense
People who are prosecuted for their first offense are often treated less severely than repeat offenders in courts of law. For example, a first offender may get a lighter jail sentence, or a smaller fine. The reason is because first offenders are not seen as habitual criminals, and instead are often viewed as people who may have made a mistake, but who can easily be put back on track.