Hi, Rain.
Welcome to TE!
First, be sure to check out the Mid-Atlantic forum here. There are several of us in the MD/VA/DC area, and occasionally we organize (informally) group/casual rides. That's a great way for you to meet new folks and try some new rides.
If you're in the Silver Spring area (there are several here on the boards who are), the Bicycle Place, on Grubb Road hosts a ride every Sunday a.m. 12-16 mph is a bit on the slow side for our C-ride - do you ride a road bike? - (well, today my C-ride average was 15.4, so this may be a great time for you to jump in!). Bear in mind that riding with a group is often (usually) easier than riding by yourself. So if you can do a 16 mph ride solo, you can probably hang with the C-ride. The C-route is roughly 30 miles and goes out to Potomac and back. Let me know if you'll join us...as we have an informal "If you brought the new guy, ride with 'em" policy. Your best way to learn the ride is to go with someone who's been on it before. And, the best way to improve your skills as a rider - both in terms of speed and technique, is to ride with a group. Pfunk on these boards is a new-ish rider to the shop ride. She may give you her perspective on the group riding thing.
Hope to see you around....