Well it depends on how much you have prepared already.
First step is to get into medschool, which generally involves a 3.0 or higher GPA(depends on the school), and about 20-27 score on the MCAT(note: you dont need to take the MCAT for accpetance into a few universities).
Classes that you schould take are:
English(essay writing skills)
Math (Calculas based, Statistics)
-all of which are at the University levels
After acceptance to Med School, i don't know currenlty trying to firgure that out >>>hoped i helped