As several have mentioned, this is a meaningless measure without context. Without knowing fitness level, terrain, wind, riding position, or gear, there are just too many variables that directly impact the result to have a meaningful point of comparison. That said, as someone mentioned upthread, check out Strava for your area, and using the weight filter, you can see what other clydes are doing on the routes you ride.

Also previously mentioned but bears repeating: speed claims tend to be exaggerated when online, especially in forum 41! That said, you can be assured there is someone out there who's faster than you. In fact, you can be assured there are many people out there who are faster. The big question, as Big Jeff gets at, is whether you're as fit as you think you are.

No, not exactly. At some point (or avg. speed) you'll just not have the strength to support going faster. Even assuming you're at pro level fitness, no one has the ability to add strength endlessly, so average speed is limited. The other way of saying it is that you will max out on power.

Okay, well if you're an average height, relatively young male, and lean as you say, then it's very likely that, if you're fit, trained, and strong, you can generate enough power to hang with, and even pace, an A group ride on flat and rolling terrain. When it starts getting hilly, though, power to weight ratios rule. You can bust a lung to keep up on the short hills, but if a lighter rider decides to bust a lung on the same, you'll get dropped. On mountains, like, long, steady climbs, there's really no hope of hanging with the fit lightweights.

But all of this is okay, and I guarantee that if you are well-trained, fit and strong, even at 200lbs, you can be assured that there are many riders out there who are slower. For sure.

My advice is to keep training and do some group rides. You'll get fitter, and have a better sense of perspective. No matter where you fall on the speed spectrum, the important thing is to ride, have fun, and to push yourself a bit.