HELP. Does anyone have past experience with underage drinking?

Ok, so heres my problem…
Just the other night me and a buddy of mine were caught outside past cerfew. The police officer claimed that he had smelled alcohol on my breath. I was given a breathalizer, but i wouldnt breath hard enough into the tube because i have a asthma and a lung disease that constricts my ability to breath in and out. The officer thought i was trying to “bullshit the device”, and i was issued an underage drinking citation. I want to fight it infront of a judge and plead NOT GUILTY. I did not have any alcoholic beverages that night. Does anyone have any advice for me that would help my case???