You're a juvenile. Your parent or legal guardian will receive a letter from the Department of Juvenile Services to bring you in for a meeting with a case worker for DJS. At that time, you will have a discussion about this case and whether you will be recommended for an "informal adjustment" of these charges, which you would have to agree to, and which would also have to be agreed to by the prosecutor's office. On first offenses, this is common--a recommended informal adjustment involving community service, a class or two, drug counseling and urine tests, in exchange for which the case does not go forward before a juvenile court judge and will be closed out without a finding of delinquency. If you are not offered the informal adjustment, or if you and/or the prosecutor reject that route, then the case would proceed to a hearing before a juvenile judge. Your parents will be ordered to retain and pay for private counsel for you at any such trial, unless they qualify for the Public Defender's Office. You are also entitled to have a lawyer represent you at the initial meeting with the DJS case worker, but at your parents' cost. A lawyer early on can help steer the process in a direction which benefits you the most. Because this is a juvenile matter (it does not matter that you turned 18 after the offense), you will never have a criminal record nor will you ever have a conviction, so you do not have to worry about this coming up in any future background checks, as all juvenile records are sealed and not publicly accessible. Also, do not post further facts on this public forum. not a good idea. Good luck to you.
Possession of less than 10 grams of marijuana carries a maximum penalty of 90 days in jail and/or a $500 fine. A conviction, even if you avoid jail time, can affect your job, your student loans (Question 23 of the FAFSA asks if you've been convicted of a drug offense while receiving aid), and your future. You should hire a private defense attorney immediately. If you cannot afford one, apply for the services of the public defender.