So most of this will depend on which college/university you will want to attend at the end of active duty. A good start will be a writing/composition class, math at the college algebra level, biology or chemistry, psychology - both general and developmental, nutrition, sociology, statistics. Most of these classes can be taken online. You will absolutely need anatomy and physiology and probably microbiology but these all have labs and almost always need to be taken in person. Good luck with this. At least you can get a start. Try to get an idea of where you want to get that BSN so you can come up with a bigger list of classes.