I was recently detained for possession of marijuana under 20 grams (half a cigarette), and the police office issued me a citation to go to court;

It is obvious from your question that you do not understand how the criminal justice system operates.  It is too complicated to try to explain it sufficiently in this type of a forum.   You indicated you would like legal advice.  Here it is:  you need to get an attorney ASAP  and discuss the facts and circumstances with him/her.  In my opinion, you should not discuss the facts and circumstances -- not even the erroneous dates, etc. -- with anyone until you consult with an attorney.   If you cannot afford to hire an attorney, I believe you need to ask the court to appoint an attorney to represent you.  In my opinion, you need to do that at your very first court appearance -- before discussing anything about the case with anyone -- including the judge.   I believe, based on the information that you included in your question, that if you try to resolve this on your own by talking to the prosecutor and/or judge in court about the incorrect information, you easily may make the situation worse -- not better.  Again, if you do not have money to hire an attorney, I strongly suggest you ask for one to be appointed when you go to court for the first time.