nurses who achieve doctoral degrees in nursing are also properly called "doctor." if you are referring to people with md or do degrees, the proper term is "physician." both medicine and nursing are independent/interdependent professions with scientifically-based practices and autonomy. neither is superior to the other; neither is responsible to the other.
for my money, what you need to know is less about schooling and more about yourself. what model of caring for people resonates with you-- the medical model, which assesses, diagnoses, and treats disease? or the nursing model, which assesses, diagnoses, and treats human responses to illness or injury?
in my experience, ob/gyn physicians come in two basic flavors, those who hate women and want to control what they can about them, and those who love women and listen to their patients. the latter are more likely to play nice in the sandbox with certified nurse midwives and nurse practitioners; those are more likely to use the nursing model for care.
if you are interested in gynecology, think about how you see women and their physical health needs.
if you are interested in obstetrics, think about how you see pregnancy and birth.
in either case, do you see yourself managing women's health, or working with women about their health?
as i said, you need to know more about what you are and then you can figure out what you want to be. cnm or anp or md/do-- all different.
if you want to follow the nursing model, you will go to college for four years for a bachelor's degree in nursing, then go to a graduate program (master's/doctoral-- doctoral will be required for nurse practitioners starting in the next year or two) for 2-6 years, and pass a national examination.
if you follow the medical model, you'll go to college for four years, go to medical school for four years, then 4 more years of residency, and pass a national examination.
but that time will go by regardless of what you do, so the question remains, what do you want to do?