I posted a reply to this thread a few days ago but I guess it got lost in the ether.
If you are looking for a "learn-to-sail" program that is convenient to your residence/work in DC, here's another vote for the Mariner Sailing School. They run a really nice basic sailing program, using Flying Scots which are a nice stable platform for beginners.
Don't worry about lack of wind -- they generally have a decent breeze there. If there is ABSOLUTELY no wind -- they will reschedule your lesson. But the Scots are actually quite decent in light air, so it's unlikely you won't sail.
Also, think of these first lessons as an initial step or building block. After completing a basic program locally, you may later want to consider a more advanced program out near Annapolis. In other words, it's not necessarily an either/or decision.