Hey,
Welcome to EMTLife!!
I'm not an American, so I am probably not the best person to answer, but hey.. I know what some people might ask and say, so I'll give it a shot.
I'm gonna guess that it varies from state to state. Which state do you live in? Your best bet would be to get on google and find out what kind of regulations are in place for your state.
For instance, you can get the highest level of industrial first aid (which is an 80 hour course full time) when you are 16. You can enter the course, do the course, and take the test all at 16, however you have an "age restriction" in place until you are 19. This means you cannot be the main first aid attendant at a job site, or on the rigs or anywhere unless there is another OFAIII somewhere in the building, or on site.
I doubt that it's going to be the same as an EMT-B because you are the ambulance, but think about insurance and liability. You may be able to take the course and the test and if you pass you get a ticket, but I don't know if you could apply and get a full time job at a stn. at 17.
Again, I don't completely know how the system works down there.. so someone will be along to give you a definite answer.
My advice: go onto google, and google your states regulations about the EMT-B course.
Good luck and welcome!