My question involves criminal law for the state of: Lousiana

Hello,
I was recently given a ticket for selling to a minor. The officer said I had checked the License and sold it to her anyways. It was during a parade but we weren't busy, just steady. I IDed everyone that needed to be carded and I clearly remember everyone I carded was at least a 1993 except for one which was a 94 and I remember her birthday was 3-9-94 bc that was the only ID I had to think twice about. I wasn't approached immediately nor shown any kind of proof that I had sold to a minor. He didn't show me the License that I carded nor the person that I carded. He just came out of nowhere and asked for my boss and said I sold to a minor. It was both me and my boss first time experiencing this so we were a little intimidated and didn't ask questions. I gave him my bar card and he asked me how do I card and what do I look at and I said their birthdate and he said no I should be looking to see if the License is vertical or horizontal and if it's vertical with a red frame around their picture then they're automatically underage because once they turn 21 they have to renew their license. So I asked is this something new but he said no it's always been like that. I had ask because I remember renewing my license at 23 not 21...I am 33 and live in Louisiana by the way...So with that being said, it made me doubt myself for a bit and obviously intimidated and so was my boss. He showed me a manikin license and what I should look at but not the license of the person I carded nor did I get to see her. He asked me if I had any questions which I was too shocked to think so I said no and he gave me a ticket and explain that I need to go to court on that date written. And after he left, the bartender next to me asked what happened and I told her and she then took out her license and showed me he must not know what he's talking about because her license was vertical and her picture had a red frame around it and she was born in 92. Then I did some thinking now that my head is clear and I'm 95% sure that everyone I carded was at least a 93 and back and there was only one 94 and nothing over...which I even remember her birthdate. Is there any way for me to fight this? Do I have to get a lawyer? And pay for all the court fees? I'm not really in the position to afford all that. Pleas help!!
Thank you!