Speed and distance get easier in a group, so you'll probably be just fine.

If you do get dropped, it's not the worst thing in the world - just make sure you know how to get home from wherever you end up. If the choice is between severe overexertion and letting yourself get dropped, go for the latter.

And if you don't already do this, a good security blanket consists of a cell phone, a credit card, a little cash, and some ID. It's a good idea to have those along on any ride, but if you're with a group that might take you farther away from home than you usually go and to an unfamiliar part of town, they're good for added peace of mind.

Have fun!