Might be good to get involved with a club like Baltimore Area Boardsailing Association (BABA) if you live on the north end of the Chesapeake Bay... or Windsurfing Enthusiasts of Tidewater (WET). They have trips, racing and fun events, and great camaraderie.
They can also help you try out different gear and base your purchase decisions on actual experience in the local conditions.
A Rio (S/M/L....appropriate to your size and weight plus the local conditions) would be good and the Rio/other boards with a centerboard or daggerboard are more appropriate for normal Chesapeake Bay conditions (specially in the Upper Ches. Bay).
I'm sure you will find that as your skills progress, you will want to travel to events, down to Cape Hatteras,
over the Dewey Beach, as well as back to the Carribbean.
What is your weight.... that is an important criteria when selecting a board.