I was falsely accused of supplying alcohol to someone under aged, can I get away with pleading not guilty?

The other night, my girlfriend and I went to a basketball game and when we arrived I went and bought 2 beers. We got there just before halftime and I bought two because the lines are always outrageously long once halftime hits. When we went to our seats, we sat down and I handed her one of my beers so that I could get situated and she proceeded to set the beer in the cup holder. About 10 seconds later a lady and another guy showed up asking for our ID's. I handed her mine and told her that we left my girlfriend's in the car. She is only 20 years old, I am 22. She told us that we needed to come with her to verify our information with the police. We go up into a little office and they gave my girlfriend a possession of alcohol by minor ticket and me a supplying alcohol to minor ticket, even though the beer was not hers, it was mine. My guess is they assumed it was hers because I had two beers. I would like to fight both tickets because she was not drunk and I did not buy her the beer. The cops did not breathalyze either of us, just gave us the tickets and made us leave the game. How likely will it be for me to get away with pleading not guilty?