I am nurse practitioner and I can give you me 2 cents. Nursing knowledge is different from medical knowledge, nurses are trained to recognize when something go wrong, to initiate interventions within their scope of practice and to alert the physicians immediately. Nurses are trained to take orders and to consult with physicians, and there is nothing wrong with it, as nurses do not go deep into etiology and pathogenesis. The route to become an MD from an RN is a hard one, because as many SDNers posted above: The classes do not meet the pre-requisite requirements for medical school application. I had to spend 2 years to retake all the classes, spent close to 10k for tuition out of pocket, and to study for the MCAT while working full time. I am fortunate to get accepted into a few medical schools on first try, but I know many of my colleagues did not. Nursing is great, dont get me wrong, its where my passion for medicine starts, and I am fortunate to be mentored by several physicians, and the funny thing is, one of the physicians are also my patient, while the other is my interviewer at one of the medical schools I interviewed at.
Now, you probably heard about nurse practitioner and Doctorate of Nursing Practice (DNP). NP is a great profession, and while I despise the world mid level and prefer physician extender, the term does reflect the limited scope of practice and the superficial medical knowledge. As I am writing this post, I am happily learning about the coagulation cascade and why I need to order a specific test and not the other. As NP, i am trained to practice it and did not go deep into the biochemical pathway. I am a good mechanic, but I will never be an engineer. DNP is just a useless degree, you can do some research and have your own opinion about it.
In short, go to nursing school if you want to be a nurse. If you want to practice medicine, then go to medical school. Nursing to medicine is a hard road, and when you have a family of your own, the challenges will be even harder.
Best of luck!