What are the chances of my possession of marijuana and paraphernalia charge being dropped?

Myself, and a few of my friends were pulled over the other night after leaving a park down the street from my house. We went there to play hackie sack and were just leaving to go home. I was not driving, because I had been drinking a little bit, so my friend was in the driver's seat. When the cop approached the vehicle he told me I was pulled over for my county sticker being covered on my license plate. Ok. Then he proceeded to say that there was a strong marijuana smell coming from the car. He asked us all the step out of the vehicle one by one, and patted us down. They found nothing incriminating on any of our bodies. They then asked to search the vehicle, and I consented, because I had no reason to believe there was marijuana in my car. (I did have an open alcohol container, but I knew when they found it that it would only be a fine since I was not driving, so I was just going to take responsibility for it, pay the fine, and be done with it). When the cops searched my car they found a small marijuana roach and a pack of rolling papers in my center console. I was completely shocked and denied that any of it was mine, and I know that no one else in the car put it there, because I would have seen them. I let people drive my car all the time, and sometimes I'm not in the vehicle when they are driving it. The only thing I can think of is that someone hid the roach and papers in my center console, and I just never knew it was there. (I am a complete slob and never clean out my car, so for me this is extremely feasible...sad I know, but true). So since none of us took responsibility for the either item, both the driver and myself were told we were going to be charged with possession of marijuana and possession of paraphernalia. I just recently graduated nursing school and ABSOLUTELY CANNOT have this charge on my record. It will ruin my life, and all over something I never even knew about. I don't use drugs and plan on volunteering a drug test when/if I end up going to court.