For me, it was great, if somewhat confusing. I didn't know anyone, and i didn't know the layout of the school. Socializing was a bit hard at first, due to my introverted personality, but i quickly realized something that was entirely new for me: Everyone in the class was friendly, even the ones i thought looked like dicks. That was when my hope for humanity reignited.
Anyways, long story short, don't sweat it too much. You're bound to be nervous the first few days, but you'll get used to your new class quickly. I know i've never had so many friends in the same class before. :U