If you haven't been in EMS for a long time, you may have read about EMT-I's and not realized how niche their position really is. (I would liken it to being a warrant officer in the military...they serve a very specific, necessary role, but they don't make up the majority of personnel)
Without getting into the very detailed specifics, I would encourage you to finish EMT, work as an EMT, find a good mentor wherever you work and then discuss with them whether you should stay as an EMT, go to EMT-I school or go to Paramedic school instead.
As for EMT schooling:
Every state has its own laws regarding EMS, so every state is different. Typically: you enroll in a school that is 1-6 months long. It is fairly easy in terms of physical requirements, and fairly easy in terms of how hard the material is, but students usually have other challenges with EMT school.
It can sometimes be a little more formal than they are used to, like, call of you're going to be 5 minutes late, or you're kicked out of school. Wear a certain uniform. Complete this easy material, but it's 50 pages by tomorrow night, and you better know it backwards and forwards. Every school, state, instructor and personal experience is different. Almost all of them expect you to be fairly professional, though. Meaning, don't show up to a lab in flip-flops or to a ride along or hospital clinical in jeans.
Like I already said, every state and school is different, but, for the most part, when you finish the class and final exam, then you usually take a two part test. The first portion is often held at your school (but may be somewhere else), and you are expected to perform all of the skills you have been training for during class. (Not as hard as it sounds) Then, you usually sign up for an online exam which is taken at a testing center under some fairly sterile conditions. This test is not hard, but it is not similar to other tests that you have taken. It doesn't just test your knowledge, it tests how you reason through things and whether or not you can think critically. Some people pass this right away, other have to retake it.
After this is done, you apply for certification or licensure in your state. Schools do not typically help you get a job, but usually through the course you will have met enough people in hospitals or at fire stations or through other students, that you will most likely know where to apply.
Like I said: work as an EMT for a while, and then get some advice about your next step.
