I was a mediocre student in a decent university and I basically chose my course because bunch of older seniors we looked up to suggested that the course had good job "prospects". The only thing I discovered from that course is that I loved writing code in Fortran while doing one of the electives (I actually wrote it on paper in my exam because we didn't have access to computers). I call that my the most lucky and important break.

I never worked on anything related to what I mainly studied and am thankfully programming now (not in Fortran though) and know that this is what I wanted all along.