You should definitely learn it and if that requires bluntly asking to be put on it, do it. I believe every electrician should know at least the basics of fire alarm. I am also third year and I do a lot of F/A. In fact where I currently am, I have by default become "the" fire alarm guy. I'm lucky because I learned from good people. I've mostly worked on Notifier and Honeywell systems. I would like to eventually get my CFAA certification.
Fire alarm is actually easy, but the important thing is it needs to be installed with a degree of finesse to prevent having to troubleshoot it later. Securex/FAS is delicate wire with flimsy insulation that gets nicked easily. Troubleshooting is where the real fun begins and is also why a lot of people are scared of it. I've found that many construction electricians are just not great troubleshooters because they haven't had to do a lot of it. Many also don't have the patience.
You will use your meter A LOT during troubleshooting because you'll constantly be measuring voltage, resistance and continuity. If you don't own one, buy one. It's not optional if you're going to work on fire alarms. I don't have a fancy one, but it would be nice some day. The thing to understand about fire alarm is the way the system and its devices operate and what each thing is trying to accomplish. Otherwise your average system depends on you understanding some basic DC theory, basic electronics and basic relay control.
You can get pigeonholed into doing F/A work when you don't want to, but it also has a lot of perks like job security and the fact that you aren't fighting with huge conductors. That's fun sometimes, but not most of the time.
If you want to get started I would first start reading about the differences between a Class A and Class B system.
