Open Question: Before a job interview should I straighten my hair?

I have really curly hair that I wear in a layered bob. My roommate says straight hair is more professional-looking because it's "polished," so I should get a great blowout. I straighten my hair about twice a year, so I'd feel like I was making kind of a false first impression. But I really want this job. It's a desirable position, and there'll be a lot of competition, so I'd welcome any edge I could get. Do you think curly vs straight hair would really make a difference?