Step 1: Write down everything you like about EMS - people you've met, experiences you've had, classes / courses you've taken.
Step 2: Look at the list above and pick reasons from that list as to why you want to go to EMT school. Was is a good class? Did an EMT/Paramedic perform especially well at a call and inspire you? Were you at a call that you wished you could do more at?
Step 3: Envision yourself standing there with an EMT license in hand and a bunch of choices in front of you - do you want to explore fire/EMS, transport, in-hospital EMS, etc? To get to one of those you need the EMT license first. Write down what you want to do and how having an EMT license will help you further those goals
Step 4: For gods sake, use a spell checker. I am pretty sure having an "enterence" essay replete with spelling errors won't help your cause. We all make typos / brain farts; use the technology available to help catch them. A good proofreader doesn't hurt either; even as just another pair of eyes they can often bring perspective on something you didn't see while writing.