If you see others bunched up in a loose group and they are doing your speed or a tad more, ask if they mind if you stay with them. Being in a group shields you from having to bust the air up all by yourself and will save you a lot energy and get you to the line faster.... assuming you didn't pick a really slow group. If riding in the group doesn't feel easy then the group is probably too fast for you. Find a slower one.
If you see a group looking real organized and in a single file column, then those people are serious about their cycling. Give them room if you happen to notice them coming because they'll blow the doors off your bike, if your bike for some odd reason happened to have doors. <grin> Some of those groups are actually pretty friendly and if you actually are riding well they'll sometimes invite you to ride with them as long as you can. But just be sure you understand what a paceline is and what their methods are. Usually if they do ask you to tag on then someone at the end will tell you how they go about pulling on the front, for how long and what to do when you fall off.
Regardless of whether you are riding with a group or not, make sure to let others behind you know when you are going to turn or get off for rest stops. Not everyone will stop at rest stops so if you don't say or signal, then they'll expect you too are passing it up. Might plow into you as you slow or turn. Though IMO, they might be more at fault, but on a ride like this you have to expect everything.
Enjoy. Most are century rides are pretty social. A few cyclists take then a little too serious. But hey, to each their own. Just enjoy it.
Last edited by Iride01; 06-04-22 at 04:06 PM.