What does it take to become a first-time director?

This week I borrowed from our local library a copy of "Whip It" which was Drew Barrymore's directorial debut film about roller derby girls.  (I enjoyed seeing the movie before--I'm a real sucker for feel-good movies.)  With the DVD sitting in the passenger seat of my car as I was driving home, I began wondering how difficult it was for Barrymore to convince some risk averse studio to hire her as a first-time director.  After all, at some point in the future, I am hoping that some school will take a chance on me as a first-time administrator.

I wasn't able to uncover anything juicy on the internet about Barrymore's selection as director.  But I did find this snippet from an interview of her by filmindependent.org:

Interviewer:  Since you were one of the producers on it, whom did you have to convince about hiring you as the director?

Barrymore:  We ended up doing it with Mandate Pictures, which is a finance company. I gave them my pitch and my vision. Nan and I believe in doing the homework. I told Mandate, ‘this is where I see it visually...and the economics of what I need to make the movie.' You have to be able to back yourself up and explain everything. You can't just go in there and say ‘I want to direct this.' As a producer I always like to think that the director must keep their promises.

If I were to make any analogies to being hired as a school principal:  1) have a compelling vision, and 2) be able to articulate it down to its minutest components.