keeping you in my thoughts loni!! No matter what, like everyone said....have fun. As for the 300+ riders, after the initial start they'll all sort themselves out and you won't have crowds like that to deal with the whole ride.
My first organized ride I was soooooo afraid.....same thing...afraid I'd cut someone off and they'd fall or hit someones tire
, or run into someone, but it wasn't that bad. Foot races were rougher to start than this!
I also had a buddy who sheltered me at the beginning, have you talked to your BF?...let him know you're nervous and to stay with you for the start? He should be able to shelter you some until everyone gets themselves sorted out.
Let us know how it went when you get back!!
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, champagne in one hand, strawberries in the other, body thoroughly used up, totally worn out and screaming: "Yeah Baby! What a Ride!"