Your probation is probably unsupervised (meaning you don't have to report to a probation officer) so all you have to do is attend driving school (I think you can do it online on your computer) and, if you don't get another speeding ticket during the 6-month probation period, the original ticket will be dismissed and will not be reported on your driving record.
Since you have already pleaded not guilty and the judge has issued a sentence, I don't believe there is anything you can do at this point, practically speaking, other than attend traffic school and successfully complete probation. If you have the money and you want to fight it, I'm sure there are attorneys who would appeal the judge's decision, but in my opinion, it would be a waste of your time and money.
I agree with Andrea. By the way, where do you work that you get off at such a late hour?
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