I think you should give it a try. Group riding can be really fun--if you find the right group.

I would add this to the clipless pedal "issue." On one hand, I agree that you should do what makes you feel comfortable. On the other, I think there's something to be said for feeling confident unclipping and stopping with just foot in an emergency. I can think of a number of times that I've had to unclip and stop in a real hurry, i.e., without really even thinking about it. From that standpoint, I would encourage you to practice unclipping with just one foot. Always make it the same foot and I assure you that it will, in time, become second nature. I'd suggest going to a parking lot or quiet park and just doing it over and over again.