Hire a criminal defense attorney to represent you. There might be options in your jurisdiction available to you short of a conviction to the charge. Local counsel will assist you.
I am trying to give you a general answer to your question. We do not have an attorney-client relationship by this response on the avvo website. I have not been retained to represent you. I am licensed to practice law in Kentucky and in federal court in this state and the Southern District of Indiana. You need to seek legal advice from an attorney licensed to practice in your area..
Even after the passing of I-502 it is still illegal to possess MJ if under 21... However, there may be other search and seizures issues that might be applicable to your case, which is why it is important to speak with an attorney. I suppose there may be a defense as the medical marijuana care giver that you would want to go over with an attorney as well. Did the officer suspect that your had been driving under the influence of marijuana? Obviously that would raise several other issues and concerns.
Yes, you do need a lawyer. Possession under 21 is illegal, but if you are a medical marijuana caregiver, there may be an affirmative defense. I published a law review article on medical marijuana law in Washington state. You can find it on my profile.
If you want to talk further, contact me directly.