It means you have been charged with class B misdemeanor possession of marijuana. The maximum penalty is up to 6 months in the county jail, up to $2000 fine, or both. In addition, a conviction will result in a drivers license suspension and surcharges on your license. Treatment of marijuana cases vary widely from county to county in Texas. It's not possible to say what any given county will do, but in any event you can look forward to a minimum of some good ol' counseling, some community service, and sobriety.