This Board Has Become Unbearably Negative...

el mejor

You'll be Ok, and you'll bring something the gunslingers don't have: knowledge of how to actually run a few parts of a business.

You’ll be fine.  I was a history undergrad and finance MBA.  Just show up and do the work and there is zero chance of failure.  Our moto: No muss, no fuss, B+.  We used to play “Gunner Bingo”.  We had squares for each gunner in the class and made a mark when they raised their hands. When you had a winning card, you had to raise your hand and use the word “Bingo” in your answer. Needless to say, my buddies were the B+ students sitting in the back and sneaking out for beers at Dominick’s. It seriously is not that hard, but you learn a lot. 

I know when to shut up to avoid looking dumb.

Then you're already smarter than many people in the world - including me on occasion.

Seriously: Congratulations, best of luck, and go kick some ass.

Work on public speaking and presentation skills. I was surrounded by egg heads who were incredibly smart, but once we got to Speech class I figured out what their achilles heel was, They couldn't talk in public! Great all gathering all kinds of data and analysis but couldn't explain it in a public setting.