How did you get your start in commodities?

I'm trying to shift careers from manufacturing accounting to energy. I have the opportunity to work as a risk/product control analyst at a large power company in their market operations department. The job seems interesting, but I've read many horror stories about getting pigeonholed in the back office.

I'm not sure where I want to end up, but trading, credit risk, and FP&A/CorpDev all seem like interesting paths, especially in the power/utilities space.

I've heard that commodities are a marathon not a sprint, and that you don't have to start off in a prestigious place like an investment bank to be successful. Is that true? Can I move out of risk/product control into other areas?