interested in a career in corporate services/finance

So I graduated with a major in biology intending to apply to medical school this upcoming spring; however, I am wondering if this is actually the right fit for me. I'm interested in getting into corporate services such as i-banking,trading etc. How does someone from my background without any finance experience land a job in Wall Street? I know some of you think I'm crazy, but just trying to find out more about the field from people who are there.

thanks.