Good advice from everyone here. The metric centuries that I've done: first one I found a woman who was riding my pace - we finished together, second one - rode with various people throughout ride and finished by myself, 3rd one - found a group of guys that I could keep up with and finished with them. It's about the journey and the ride YOU want to do. Start off together and go your seperate ways if necessary.
"You can't get what you want till you know what you want." Joe Jackson
2006 Cannondale Feminine/Ultegra/Jett
2012 Trek Speed Concept 9.5/Ultegra/saddle TBD