Speed ticket-shall I go to the court

Last night, I drove around 48 miles on the speed limit road of 30. The officer said he's going to give me a brake so he wrote down my speed as 39 instead of 48. I got fine of $80 and one point.
My question is shall I refuse to pay the fine and decide to go to court and talk to the judge. Because it's almost 9Pm at night I can't really see the speed limit sign plus it's not a big speed considering the number of 39 miles and 30 miles. Do I have any chance to win this case based on my above situations?
Very frustrated. Thanks for your advise.