Hi honey
Well first thing, Nursing at the BS level is an UG degree just like anything else. Now I don't know what year she is at, but if she is undecided in her major, then she should apply to the nursing program. Nursing program GPA's range from 2.5-3.0 depending on the school. Seeing how she is thinking about medicine, she may have taken many of the nursing prereq's. She will need to complete those with no lower than a C or B(depending on the school) in each class. If she has lower, she can retake it. I listed the prereqs at my school on a previous post, but here they are again
Psych 101
Abnormal psych
Anatomy 1
Physiology 300
Pathophys. 412
Chemistry 1
Micriobiology 301
Psych Statistics
Medical Ethics
Biochem Pharmacy
there are a few more but my mind is drawing a blank.
Basically have her contact the nursing departent at her school for the requirements and go from there. She will fill out an app like anything else.
Now nursing is not an easy program, I would have never thought so if I had not done it. There are a lot of projects

Tons of studying, and oh pay attention in her prereqs bc you don't want to have to try and relearn phys and anatomy when you are learning about health assesment.
Micro ad human phys at my school seem to be the toughest prereqs that people need to get through. It's the same classes that the school offers. There are not separate ones just for nursing majors. So she will take them with the pre PT's, pre OT's, pre pharm, pre meds etc.
Now as for diploma programs I have learned a little about them in nursing hx but I really have no idea about how to go about that. So if that is what she wants I don't know. But, if she wants to go on to grad school for nursing her best bet would to be to get her BSN now. We do have a lot of Assoc. RN's in our program with us.
Good luck any other questions let me know

Oh I go to SUNY Buffalo, and will be graduating this coming May, and also am applying to medical school.