National Novel Writing Month

I did it. I went and signed up for NaNoWriMo and now I'm having buyer's remorse.
What the heck am I thinking?
I've never signed up for this before even though I've known about it for years, but I know me, I'll never write 50k in a month. 
I don't have the time to devote to this.
Are they insane? Am I insane?
Well, yes, the obvious answer is yes.

Well, whatever, I'm committed now.

Besides, I've had a story in my head for years that I can't ever get out. I've rewritten the first chapter in so many variations and then tossed it, it's ridiculous.
This is it's final chance.

Write it or Kill it. 

I should probably sound more enthusiastic, right?