I don't know your age, but it's not easy to be a firefighter. EMT B, Firefighter 1 and 2 certs needed, probably a college degree. Paramedic would increase your shot. Then work for free for maybe 2-3 years as a reservist at a department that has such positions. Then, and only then, might you be able to be hired. It's important to remember that for every open position, they have probably 200-800 applications. Many of those are trash (HS graduates), but many are not. You need to be at the top of the pile to even have a slight chance of a job, and if your not in your prime, it's all that harder, if not, perhaps, impossible. If it's a place that has reservist positions - many do - think about it, who are they going to hire, you, or the guy that's volunteered for three years? It's not something that you can just hop careers into though, because there are too many people that really badly want to get paid to sit around all day grilling steaks.

'Scuse me while I dodge some incoming tomatoes.
Not to be the bearer of bad news, but it's not a career people can easily hop into.
Source: Close family and friends are/were FF.