Viridian wrote:Four years of college after high school would give you a Bachelor's degree. A Master's degree would take several years more.
But this is beside the point. Your character's background has literally nothing to do with what you use her for in the story. Though stories will explore fantastical ideas, there's barely a modicum of plausibility behind a college-educated woman suddenly seeking out a quicksand pit and killing herself for sexual pleasure. There are plot elements here that could work, but as the writer you should weave them together in a more meaningful way.
It is possible for someone to get an MD at that age, but it is quite difficult, it can happen if someone gets a head start on college if they excel in previous education.