I think you should find your research interest, says, finance or accounting, etc, by yourself. Your standardized tests and your undergrad are good. As my research interest is corporate finance with a concentration on corporate governance, when I see your RA experience, I assume you're interested in finance (or accounting). But I don't know. Moreover, you said you didn't take enough math courses, but we don't know what courses you took? Did you finish Cal I, II, III, probability and statistics, or any other proof-based math courses, says, real analysis? So you better take some more courses, talk to your professors, and see what makes you interested in doing original research.