Hey congratulations!!!
I did my first mb race a couple of years ago......I didn't know anyone, had put clipless pedals on the day before (!), and got there late. I just had time to put my number on my bike and line up and the guy said 3-2-1 go!!! I didn't know how long the course was or anything!
When he said go, I just went as fast as I could anmd found myself in the top three....for about 30 seconds, then everyone started passing me!!! But I did ok in the end...and I def caught the bug.
And everyone was so nice, and so helpful......now I go mostly for the comeraderie, although I have progressed to Sport, and have my rivals I keep an eye on during the race!