Up in Glen Echo (MD) on Thursday nights they have Blues Dancing lessons. I have gone the last few weeks and really enjoyed myself. Cover is $8 and the lesson starts at 8:15. It's in the Back room of the Spanish ballroom. So if you head between the carousel and the bumpercar pavillion you should see steps and an easel/sign saying you're in the right place. This gives a pretty good idea of it. Fairly freeform and soulful.
Don't worry. You and I will look much more awkward. Just be willing to laugh/smile about it and try again.