expired registration

State: Illinois

I recieved a ticket yesterday because I forgot to get my license plates
renewed. They expired at the end of July. The Police officer told me that he
couldn't just give me a warning because it has been past 19 days and
that he was not allowed to do that. I find this hard to believe since yesterday
was the 19th. Is this true? And if I go to court will I be able to get out of the ticket if I get my plates renewed today? I do understand that I should have taken care of this in the first place, but I have been busy and it was an accident. I know this is not a good excuse, but I feel that I could have been given a warning to take care of it. The state doesn't even charge a late fee until you are 30 days past due.

He did not have to ticket you, but since he did you will not normally
be able to void the ticket if you were indeed past your deadline.