You will want to obtain a lawyer to assist. You do not want the possession on your record for obvious reasons and also because it will preclude you from qualifying for various types of federal funding including student loans. They don't have to read you your rights if they are arresting you, but if they did not and you confessed, that confession could be kept out of evidence. Hope that's helpful.
Your best bet is to reach out and consult an attorney to help advise and assist you in this situation to help you in either keeping this off your record or minimizing any repercussions.
You did not give enough facts to really determine what course of action to take. If you were cited with disorderly conduct, it may be just a simple ordinance violation, which is not very serious. You never mentioned anything about having less than a gram of marijuana, so I'm not sure how that relates, however if you were charged with this as well, it is important to speak with an attorney, as a drug conviction, even for simple possession can have serious implications.
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