Should I plead not guilty to MIP charge?

I received a Minor In Possession of alcohol charge at my house the other night. The cops came and talked to my 22 year old drunk roommate who then proceeded to tell them that I was inside, so they asked to see me and when I walked outside I was issued the Ticket. They never saw a drink in m hand, smelled me for alcohol, or gave me a breathlizer. To tell them I had maybe three beers at the time, but was not drunk in any manor. I have no prior arrests, should I plead not guilty because there is no evidence to support that I was drinking, and seeing that all the beer in the house could be explained as belonging to my 22 year old roommate.