Got introuble need help!!!!!!

Ok i got busted again. was at the hershey concert(breakin benjamin, staind, 3 doors down) in the parking lot yesterday and we where gonna drink some beer. welp we get them out and the girl in the back seat just starts drinkin like shes allowed and of coarse MR. undercover cop knocks on the window with his badge. so basically fcuked. any ways he writes us up for a NON-traffic violation of having beer in hand and being under 21 and smelling like beer. but they only write up 3 of us out of the 5 ppl in the car and they where gonna do a breathalizer but then decided they where not gonna. so no one got a breathalizer. they said the findes are ususaly a little under 300 and i will prob lose my liscence for 90 days at the most. what should i do with this? should i go with not guilty