You might also consider taking a DMV Driver Improvement Program course to add +5 good points to your driving record (check first to make sure someone under 18 gets the bonus points) before you go to court. If the court orders you to take the course, you can submit the completion certificate. However, if you do not take the course and the judge orders you to take one in exchange for a dismissal of the charge, you won't get the +5 good points. Good luck!
Virginia is strict when it comes to expungements. A conviction, barring something extremely unusual, will not be expungable. Even dismissals are sometimes not expungable where the defendent pled guilty or incurred some form of punishment (drug court, community service, etc.) I agree with the other posters: get a lawyer concerning that appeal.