Here's a list of all school's in MO and their pass rates. Board of Nursing
One thing to evaluate when you're selecting a school is the pass rate. What good is going to school if you have trouble passing the licensing exam, right?
You'll notice on the school list there are schools that offer practical nursing - this means they're LPN programs. Then there are school that offer professional nursing - this means they're RN programs - they're further broken down into ADN or BSN programs.
There are a lot of options in your state - I would suggest going through this list and finding schools near your area and visiting their websites to look into what they require to get into their programs. Nursing school admissions can be greatly competitive and some schools may base their admission criteria around GPA, some may do a lottery, some may require other entrance exams, etc. Although most prerequisite classes are similar, some schools may require class(es) another school may not. It's all up to the school.
After you find a few schools that interest you, make appointments to go see an academic advisor there. They'll get you on your path to start taking general education classes and satisfying your prerequisites.
Nursing school isn't easy. It's doable. I didn't go back to college until I was in the workforce as a high school graduate for about 8 years. When it's your future at stake, you do what it takes to make sure you get good grades. I was able to work FT while I finished my prerequisites. After that, I had to quit my job and do the nursing program full time without working. There is financial aid and loans available to help with living expenses.
Associate's degree or BSN...personal preference. If your goal is to be a RN, it doesn't matter. If you can imagine yourself continuing your education someday to become an educator or nurse practitioner, a BSN may benefit you. In my case, I realized it was going to take me two years to do my prerequisites and two years for the nursing program no matter if I got my ASN or BSN, so I went ahead and pursued a BSN. I'm glad I did now that I plan on applying to graduate school this fall.
My best advice is to just go for it - get organized, have a plan, get good grades, and make your academic success your priority while you're in school.