Forensic Medicine as a specialty is not taught at a university level, it is taught at a post-post medical graduate level. You must attend and complete med school and residency in pathology. Then you can apply to fellowship programs. There are a dozen or so good ones now, but by the time you get there, what is good now, may not be the best then.
Don't worry about that now, worry about that in your second or third year of residency.