most nursing schools have a gap period between application and admission. Prerequisites for nursing in my state school pertinent to medical achool application only include:A&P, Microbiology and 1 chem class.
so if you do the right thing take Micro, chem I and A&P for science major, you'll still need general chem II, physics I &II, organic I and II, biochem + some upper level biology class, not to mention its a bad idea to take organic I and II in the summer. so that means you need to take extra time to take organic chemistry seperately. Dont forget those classes comes in certain order, you need to take general chem first before you take organic chem, no biochem class before you can make it through organic chem I and II. so thats a two or three year plan.
In nursing school, generally, you'll never have time to jungle in between nursing and premeds class, otherwise you grades will suffer and no medical school will like that. you need make as many As as possible. being in nursing doesnt give much of a leeway on GPA.
once you are graduated and ready to "build your bank", first year nursing is very demanding mentally and physically because theres so much you need to learn. managers dont like the idea you need to adjust your schedule because you have schools to attend. once you pass the stage of being a newbie, two years has already gone by.... now its time to take some flexible shift and make adjustment for your tuesday and thursday classes.
Been there, done that, not fun, I never rest for a minute in those six years, I didnt have a boyfriend I need to entertain except the first two years and my parents even helped me out on tuition. I dont have kids needing my time and attention. It did just take me six years to finish a BSN+ all the premed classes and my checking account still suffered because I had to pay all that money for my premed classes.
If I'm the OP, I will think about it this way, I dont want to lose a year practicing as a doctor, so I'll do my best as a biology major, try to get in in my senior year. if thats not happening, then I may go back to nursing and it'll take me only two more years to finish all nursing classes.
Enough about all that nagging, the OP could just ignore me. its ultimately your decision...
The good thing is you dont have to decide now, you can start taking classes and test the water first, if you make all As, why not go straight ahead with biology and medical school? I'm not saying nursing school is easy, most schools require a 3.5 and above to get in.