I was arrested for marijuana possession under an ounce and loitering. This is my first offense. Is there anything I can do?

It's St. Patrick's Day weekend, I'm nineteen, someone at work asked me if I wanted to buy a gram, I would rather enjoy an altered state of non-violent conciousness than do some underage drinking, I went to a park at midnight, sat at a table, started to roll a marijuana cigarette, a police officer rolls up, I throw everything on the ground, I'm arrested for marijuana possession under an ounce and loitering. I'm waiting to ship out to basic training for the Air Force and a misdemeanor will prevent that. I understand what I did was wrong and will never do it again and I don't want a very tiny amount of marijuana with no intent to sell to ruin my future when in another state, I would have just walked away. Is there anything I can do? I feel like I should mention that there is no THC in my system at all.