I took a stand up comedy class and checked out another one.

They teach how to tell jokes. I am not a natural joke-teller, but rather am pretty good at telling very short, funny/odd stories.

Question: Am I dead from the start?

Question: Must I learn how to tell rapid-fire jokes that goes against my nature?

Thanks for your time; this is a smart forum. Hoping to get good advice (desperate!).

The worst thing you can do is to go against your nature. There are such a wide array of comedic styles out there, I’m sure your style fits into one of them. If it doesn’t, start a new one.

If this class is teaching you that there is only one way to tell jokes, get your money back.

Find your niche and run with it. If you’re not buying 100% into your joke-telling style, the audience won’t either.

It can take a long time to find your voice (as you called it “nature”).  Even longer if you are going into different directions to please people, bookers, or industry. 
The last comment was correct.  If you have your nature (voice),  get on stage as much as possible.  Learn to be comfortable and confident with your voice.  You’ll go a lot
further faster by staying to what you believe and talking about what inspires you.  Glad you learned it now.  You can see we showcase many talented comedians with different styles.
check it out.  http://www.profusiontalent.com/comedians.html