medicj, great advice!
The ride along will tell you much, I highly recommend it. I highly recommend that if you are doing it for a paycheck only, you are looking at the wrong field. You're better off looking for work doing something you love doing (we're at our jobs at least 1/2 of our time, why be unhappy!) and remember: 1- Medics are VASTLY underpaid, especially considering the level of hazard that comes with the job; 2-People in it only for the money generally don't do well in it, 3-You can at times work yourself to the bone, and if you don't really like the work, 12-16 hours of this shift after shift after long long shift will really really suck.
Be sure you can hold your own in a crisis management situation...if you are the type to be caught in the middle of a brewing fight between a group of huge drunk guys and are able to diffuse the situation with your interpersonal and negotiation skills, then you will make an excellent EMT. If you are the type to quickly walk away, almost pissing your pants, this isn't the field for you.
Not only are there medical and patient safety issues to consider, but also your own personal safety issues as well- oncoming speeding cars, violent family members, gang activity, psychotic people, patients with weapons, exposure to copious infections bodily fluids (consider the AIDS-dementia patient with projectile vomiting of blood and watery bloody diarrhea while you are starting an IV in the back of an enclosed ambulance space- not an exaggeration, this happens a lot). Remember you will go into scenes that are not controlled, such as the scene of gang violence, car accidents, into peoples' homes, exposure to hazardous conditions, dead bodies, etc.
Now, if knowing all of this, you are thinking Where Do I Sign Up?....then welcome to the EMS field, my friend, you will make a fine EMT...