Your not too old and if you are in the shape that you posted you would be able to pass the physical portion of the entry exam. As a "new" firefighter on a paid department you are going catch shit and have to run chow among a bunch of other new guy duties. Some older employees have difficulties in being the "new guy". You need to seriously ask yourself why you want to be a firefighter. None of the movies or TV shows are close to what it's really like. Most paid departments won't allow you to even test if you are not already an EMT, so if you don't already have it you need to look into getting it.
The requirements for being a volunteer are not as complicated, a lot of communities have difficulty getting enough.
I'm a Captain and coming up on my 19th year anniversary on the department that I work for. I absolutely love my career and work with a awesome group of people. It's not all puppies and rainbows and you probably won't get rich doing it, but it's a very rewarding career, lots of laughs (and gruesome shit), and you definitely see a side to the city you live in that you really didn't know was there.