Should I attempt my first chaingang? Too slow?

Depends how good the club is at working together as a team, rather than several individuals cycling at full gas?
I've had mixed experiences.
One was a well co-ordinated rotating chaingang, which happened to be random strangers working together on a sportive. And I've came across a club ride where guys were popping off the back every few metres, think we only managed one rotation !

But to be honest if it's a good club, it'll be easier than you think. When you're at the back you'll be effortlessly cruising along at a surprising speed. It's only hard at the front with the air resistance, but if you struggle just go to the back again. I know of a club who don't have a set time at the front, the fitter racing snakes are happy to be at the front longer and some of the less fit guys only take a turn on the front once every leap year.

My only advise is point out potholes to the guys behind you and keep in a straight line with the guy in front, it scares me when a guy starts erratically squirreling across the path of everyone else or doesn't understand cycling in 2 lines.