Qualifications
An epidemiologist is an expert, and like all good experts, he or she needs of lot of framed pieces of paper with Latin on them. Yes, we're talking about degrees.
This isn't some sort of namby-pamby science like chemistry where you can pick and choose exactly how many smarts you'll allow into your brains on a whim. Oh no, this is some real-world, hardcore science that requires you to have a full-blown master's degree in epidemiology to even think about practicing. Okay, that's not true. You can think about it. Go on, have a think about it. It's on the house.
You'll have to go to school until you actually run out of school to go to, and that's a good thing (we promise). The world needs people like you to be prepared. A lot of what epidemiologists do is prediction, and we need the people who make a living of guesswork to be, like, super crazy awesome good at guessing. Especially when we're talking about public health (source).
You're also going to need to work on your public speaking, or at least your interpersonal confidence. Epidemiologists are the only ones who speak the language of epidemiology, and therefore it's on you to explain things. You'll need to explain your views to peers, other experts, and even government officials. There's no point in discovering danger if you can't get someone to act on it.