I agree with Lauren, the website she provided offers great answers to your question.
When I was in medical school, most of the other students had majored in pre-med, biology, or biochemistry. I also majored in anthropology, where I was exposed to forensics when I took biological anthropology courses. I really like the recommendation to take undergraduate courses in forensic science, criminal justice, or psychology.
Forensic Pathology is a fascinating job, but it can be emotionally very difficult. It is a long road of education to be a doctor, but keep in mind that you can change course at any point in your education. Education is never wasted if you stay curious about the world around you. Good luck!