Before you commit yourself to this field of study you should know that there are virtually no full time jobs for forensic anthropologists anywhere in the US. Everyone I know who does forensic anthropology does it more or less as a sideline. The typical forensic anthropologist is a PhD level college or university faculty member with an appointment in physical or biological anthropology.
You are looking at the following periods of study:
BS or BA: 4 years PhD: 6 years
You might do better to consider a career in crime scene processing/reconstruction. The highest degree required would be an MA or MS.