Are you a parent or worried about becoming a parent? I'd be happy to pass on my advice, but was curious why you posted on MomMD.com. You may get more responses on Student Doctor Network's nontraditional forum, since you are starting on prereqs for medical school a bit later in life, but usually MomMD is more focused on advice for those struggling with going into medical school, being in medical school or post-medical school life as a doctor with children.
Advice - why nursing? Do you want to be a nurse or a doctor? I would decide which one first, and then pursue that path. Nursing often has different classes in it that won't fulfill your prereqs for medical school and won't take you in the direction for applying as directly...
As far as premed - major in something you enjoy - art, history, English, biology - whatever. Take the prereqs for medical school, a year of General Bio with labs both semesters, a year of General Chemistry with labs both semester, a year of Physics with labs both semesters, and a year of Organic Chem with labs both semesters. Many also take some upper levels just to get a further base for themselves like biochem, genetics, cell bio etc.
In your case, your GPA is very very low for applying to medical school. I would try to get it up to over a 3.0 - aim for at least a 3.5, but the average is nearing 3.6 I believe now for accepteds.
A little over a year out from the fall you want to start medical school in April or May - you will take the MCAT. Most shoot for a score of around 30, but again, the average is going up to around a 31 I think.
Do some hospital volunteering, try out shadowing doctors, and get engaged in research/clubs/service at your school. These are all things that help your application, and with the clinical experience - help you know if you are a good fit for becoming a doctor.
I would say you have 2-3 years of classes ahead of you, so you have plenty of time to really feel out what might be right for you - medicine or not.
Best of luck with this big decision!