What are the penalties for first time marijuana possession of less than one gram?

If you are telling us the whole truth and there is no other criminal history (depending on the state this occurred), you should end up getting a PreTrial Intervention/Deferred Prosecution Agreement which will likely lead to a dropping of the charges once you've completed all of the court's requirements. Expect a fine in the neighborhood of $200. We would recommend contacting the Clerk of the Court and find out who the Public Defender would be in your case. Write them a nice letter outlining your fears for having a record at this young age, you are a conscientious student that made a critical error in judgement. Let them know you are aspiring to greater things and hope and pray for "an outcome that will not erase your dreams." With a little luck, this nightmare will be behind you in 2-3 months without affecting your life down the road. And, stop driving around with weed, smoke in your home.