Good luck in your search.
Long and Foster
White Oak/Silver Spring
The next step would be to get with a qualified agent who specializes is selling homes in your area of choice and "go shopping". Of course this agent would want to sit down with you for a brief consultation first, especially being as though you're a first time purchaser to go over the entire process with you from A-Z. So you'll not just be a home buyer, but an INFORMED home buyer.
Much success to you in your home search...
With the current interest rates and tax credit incentives, it's a great time to buy your first home. Good Luck!