There are definitely things you can do to minimize your risk when renting the property. And the rental market in Ashburn is moving much faster than the "for sale" market - 21 days versus 100 days on the market (average).
But consider this as well - the rental rates are very low so you should definitely run a cash-flow analysis. Look at what you could rent out your property for and then compare that to your monthly payment + HOA dues + about $75 to $100 per month in maintenance (average). See if you're losing money, breaking even or making money each month and take that into consideration.
And know that there is typically a one to two month lapse between when the current tenants' lease runs out and when the next tenant moves in.
Even if the bottom is near, real estate prices will most likely go sideways for a while afterwards, probably 3 to 5 years. As long as you can hold on to the property for at least that long, you will see your property's value go up. If you plan on selling and/or moving prior to then, you may want to sell now.
As many have said in their answers below, real estate is one of the greatest long-term investments you can make. All I'm saying is that you take everything into consideration and weigh the pros and cons. If you're in this for the long-haul and can afford to rent your town home, hold on and rent it out. If not, then you may want to sell. Just depends on your personal situation.