Speaking from the standpoint of a veteran ticket fighter -- pay the ticket. The reality is you have to prove that you were NOT moving faster than 5 mph. You also have to prove you were not creating a wake. Obviously if you were taking off with the intention of going faster, you were doing both of those things as that is how jetboats work. The officer will be presumed by the judge to be writing good tickets as he is a professional doing his job. He and the judge likely know each other, and have shared a docket a time or two. The officer is only on the lake on weekends, during the week he is in a patrol car dealing with real criminals so a chance to come to court is like a day off for him, he will show up. And then he will testify how you told him several times that this is your first time out and you don't know the rules very well.
I'm not trying to be a dick, I'm just telling you that you should man up and pay the fine.
Oh and the lake is actually in pretty good shape. Filthy? Nah, you haven't seen filthy at Elsie and probably won't until the end of next summer.