Byrdnest,
Don't get yourself stressed out yet! Just take this a day at a time. The first thing is that you have decided that you want to be a nurse. That's good enough for now...you can decide later (or change your mind a dozen times) about what area of nursing you want to work in. The beauty of nursing school is that you will get to have clinical rotations in many different areas and you will have the change to try out working in different environments.
For now, locate the community colleges in your area that have a nursing program...you will probably be able to earn a ADN (Associates Degree in Nursing) there. Make an appointment with a counselor at the school and see what you need to do to apply to the nursing program. Most schools today expect that you will have completed some basic courses
BEFORE they will accept you into a nursing program. You can get started on them right away...maybe even the January semester if you get on the ball. These will be classes like anatomy and physiology, microbiology, perhaps chemistry and nutrition. Your counselor can tell you exactly what you need.
That will be enough to get you on the path to nursing school and as you said, you are still young so you will have many wonderful years to work as nurse. Good luck to you!