There are 3 ways to train to be an RN.
1) Go to a 4 year college and major in nursing and you will graduate with a Bachelor's degree in nursing (BSN)
2) Go to a community college and complete a 2 year program and get an Associate's degree in nursing (ADN).
3) Go to a hospital based program and complete 2-3 year program and you will have completed a diploma program.
All of nurses have to take the exact same licensing exam (NCLEX). There are never ending debates about which preparation is "best" and I won't go into them here. You can look on AllNurses and find plenty to read on that.
The real difficulty is in getting accepted into any of these programs. Most BSN and ADN programs (I don't know about diploma) require that you come into the program with many prerequisites. You won't even be considered until you have successfully completed them. They can be things like microbiology, chemistry, etc. Check the local community colleges and 4 year colleges and check out their admission requirements.
Many hospitals have programs to train you to be a certified nursing assistant and that is an excellent way to start. It gives you an opportunity to work in the field and make sure this is a good fit for you. You might consider starting with hospitals in your area to see what kinds of programs they offer. As a bonus, some hospitals will assist you with tuition for you to go on for your RN or LVN degree if you are working for them.