I am also self taught, and the way got to different languages was simply based on need. I started with BASIC, and used that until I found a problem I couldnt solve well with it. So i learned something else. I used this to work my my way through learning the basics of shell scripting, VB, C, SQL. Then one day while working on a shel script I couldnt figure out how to do something so I popped on an IRC chanel for advice and someone replied with an answer that was like 3 lines of PERL code. So I started learning PERL.

My point is that i have always had a problem that drove me to one language or another once I started learning PERL, I havent come up with a need for another lang. Everytime I think there is something I can't do in PERL I find another module or coding trick that lets me get the job done. So in that sence it can be bad if your goal is to learn every computer programming language if your goal is to get your work done then it is a great day when you find PERL.

As for your case, I would just consider doing my homework a problem requiring the need for a new langauge. It never hurts to learn another way of doing things.