I am a high school senior planning to major in mathematics next year at college. My question is this: Are there any fields of mathematics which do not have a wide body of literature (maybe even just a few papers or monographs), yet have potential for further research? Please give some sources for learning about these fields, if you can.
I am mainly looking for an area of mathematics where I can reach the frontier of knowledge reasonably quickly, and hopefully even contribute during my undergraduate years. I have looked into graph theory as a possibility (is it a good one?), but I was just wondering if there were any other fields out there which might work as well.