There's a great fly angler about 30 minutes north of you near the Upper Gunpowder Falls: BACKWATER ANGLER
I've stopped in there once or twice before and they've always been friendly and helpful, and not once made me feel embarrassed to be a beginner. There's also some good spots to fish up there with easy water access and gentle wading.
Also, I read your other post about the bad knees, I've got a bit of that problem myself so I make sure to wade carefully. I recommend using a hiking stick to help you keep your balance and also feel around for deep holes or slick rocks that could trip you up. There's a few collapsable wading sticks specifically made for the job, but I actually suggest getting a pair of regular hiking poles
. For the same cost as a collapsable wading stick you get two extendable poles that provide greater weight support, can be used in the water and out, and are usually made from lighter, more durable materials. When you've found your casting spot, they can be stuck upright in the river close at hand or you can collapse it and hang it from the back of your vest near your net.