I'm in the same boat - have signed up for my first 50-mile charity ride this September. There were also 8 and 25 mile options, but I know I can do those, so went for the challenge. How/where do you bike now? I mostly ride solo, but on city roads and one of our heavier-used trails, figuring that getting used to dealing with road/trail traffic is good practice for maneuvering in larger groups. Also, I expect to bear near the back of the pack where it won't be as much of an issue