If you're curious about becoming an EMT, there's a great way to find out if it's for you: Most places you can find EMTs you'll also find trainers who can provide training in CPR/First Aid, First Responder, and full-blown EMT. First aid and CPR is typically a one to two day course. First Responder is typically a one week course the first time with three to four day refreshers every two years from then on.
First Responder training covers a lot of material with enough depth and breadth for you to be of use in a medical or trauma emergency. It gives you the basics you need to know to recognize an emergency situation, provide immediate aid, package a victim for transport, and assist EMTs on the scene.
If, after a week of trainin, you find you want more more more, maybe that's a sign that training for an EMT position is the right thing to do. Instructors are typically EMTs themselves, so they would be able to tell you what to do next. Even if you decide after a week of training that this isn't for you, you'll be better able to respond when someone around you is hurt or sick.
Just don't be surprised if your first aid kit is never the same again!