I'm confused by the person who said firefighters make good money.
I guess it depends on where you live. I have a good friend that retired last year at 57, he gets $90k pension, and health benefits. Obviously he was making more when he worked full time. I'd say that's pretty good $ in most any career. I'd be willing to bet FDNY firefighters make excellent $, and I'm sure they earn every penny.
To the OP.... absolutely, do both! Perfect fit. Good luck in your career(s)