One of my biggest questions when considering culinary school had to do with experience. How much kitchen experience is ideal to have before beginning a program?
Like most others, my 20-person class at the FCI is a mix of kitchen novices, seasoned cooks and everything in between. During the first week, it was obvious who had professional cooking experience. The restaurant managers, food writers, career-changers and "avid home cooks" hunched over their boards, fiercely gripping their knives in concentration. The experienced students – backs straight, grips controlled yet relaxed – worked faster to produce better results, typically accompanied by a yawn. But as the weeks went by and the daily assignments became more complex, the playing field evened out. Even if a student worked in a restaurant for five years, it didn't mean he had filleted fluke or made crepes a l'orange. Students who had line experience maintained an overall advantage, but the difference between them and the first-timers was less stark.
That being said, I think it definitely helps to have some sort of professional cooking background. Even if it's only a year's worth of experience like I had, it makes a difference. I compare it to having done the required reading before attending class. If you've done your homework you'll get more out of it, because you won't waste time figuring out the basics. That's not to say that complete amateur students haven't been successful. But if you want to be a cook, and one day a chef, it helps to at least know that you like professional cooking before signing up for a pricey school.
In the end, though, it all comes down to attitude. An enthusiastic, open-minded novice will probably do better than a seasoned cook who goes in with the mentality that he has nothing left to learn, only a degree to get. Like any educational program, you inevitably get out as much as you put in.