Scientific Rigor of NP Programs?

I am a nontraditional student who works in a non-healthcare field and is considering direct entry NP programs. I am a very strong and serious student, but have had a lot of trouble figuring out a career that is a good fit and so have taken a really meandering academic path. After getting a BA in Psychology, I decided that I didn't want to pursue my plan to go into academia, so I worked in several different industries before going back to school to become a dietician. I was planning to apply to MS RDN programs and, because I absolutely love to understand how things work, I took a more rigorous nutrition and health sciences pre-med option for working on my prereqs. Well, I ended up loving my upper-level science courses (organic, biochem, human nutrition science, toxicology, etc) and doing really well.

Very long story short, I realized that I'm much more interested in diagnosing and prescribing treatment, than creating meal plans, etc. I've considered going for a MD or DO, but that seems like a very long road to start in my mid/upper 30s and a decent work-life balance is important to me. After doing a lot of research, I think that a primary care AGNP would be a great fit because I want to focus on preventative care and managing chronic diseases. I'm also interested in endocrinology. Philosophically, I definitely prefer the patient-centered approach of the nursing model to the disease-centered approach of the medical model, which is why NP school is more appealing to me than a PA school.

What I'm looking for is insight about the scientific rigor of NP/nursing school compared to PA/medical school. I am fascinated with biochemistry and I am afraid I could be disappointed if the courses don't go as in depth as I'd like and I'm sure there wouldn't be much time to do additional reading about the biochemistry behind the concepts that we're learning in an already intensive program. I don't want to end up bored or frustrated with the content of the courses and I've read some things that have me wondering if that could be the case.

I'm also concerned that nursing school will be a lot of memorization, without going into enough about the "how" these things work to suit my learning style. I have a harder time with rote memorization than with understanding and remembering processes. For example, I'm currently taking A&P and, while I have done well overall, I have a much easier time with the physiology portion than the anatomy portion. I'm concerned that I won't do well in nursing school if I have to just cram a bunch of information into my head that I'm supposed to take at face value without being able to connect the dots by really understanding the details, especially in the accelerated RN portion of the program.

Any insight would be very much appreciated :)

-Kate