Congratulations! Don't worry about falling- I've seen people fall at almost every mass start- even standing still- so it isn't just you. What I would do is make sure my bike is in the right (easy) gear to start off, wear MTB shoes with good grip, not clip in until I was sure it was safe and out of the way and had a good rolling speed. You know you can situate your cleats so they don't engage by not having them exactly over the right spot.

Or just position yourself more toward the back of the pack, where people aren't in such a rush. That way you'll avoid the first few bottlenecks at corners, too.

You have to wait a whole _year_ before the next ride??? If you're at 50 miles now- you're well on your way to 100!

Nanci