Hi Alyssa, The best in being hired, is to found out want the Dept. are looking for, then go from there, because then you will know if you need a 4 yr college or most colleges offer fire academy and they will teach you everything you need to know.
At your age, I would say go to school. Get a degree in fire science. Then hire on somewhere. The reason I say this is that once you start working it becomes easy to put things off. Oh I'll skip class today, i'm tired from that fire last night. When you want to start climbing the career ladder, the degree will be a big advantage.