Great job for a first group ride. I've been doing B and C rides for about a year now and about 2/3 of the people I ride with are A riders who use the B and C rides as recovery pace. I also ride a flat-bar, steel, light touring bike and weigh significantly more and am a good 10-20 years older than most on the rides. I still get dropped or at least end up in the slow pack after the group breaks up. Doesn't matter and I still have a lot of fun and get a good workout.