Best of luck to you as you begin your program. It sounds like you would make a wonderful nurse-midwife.
All Certified Nurse Midwife programs are at the Master's degree level. Upon receiving your nursing degree, try to find a L&D position, as that will prepare you best for entering into a nurse-midwife program.
"Midwives" are lay persons who apprentice with other lay midwives to prepare themselves for their role in caring for pregnant patients. The practice of lay midwifery is illegal in many states, and, dangerous in my humble opinion. These practitioners have little or no fromal training, no hospital privileges and no physician back-up. If they encounter complications with their patients, their only recourse is to call 911.
Doulas are persons (lay or medical professionals) who offer advice, support and hands-on care to laboring mothers and families in the post-partum period. They are ofter helpful as additional support persons during labor, and help the family to transition to home by assisting with such things as personal care, infant care and breast-feeding.
There is a doula named Jamie who frequents this site and may be able to answer more of your questions.