Me too! Just this past Saturday I joined my first group (probably at least 50 bikers) and we did about the same distance and speed. Up until then I hadn't ever ridden with more than a couple guys and definitely not that speed for that distance. I thought I wouldn't make it, but I made it work somehow and several guys helped me out by encouraging me to draft them. Before we started the ride I just made sure to introduce myself to a few guys and let them know it was my first time. Definitely need to make a habit of this.