If you're interested in global politics and so on, you should definitely study it, but I think there are other ways to follow your interest that you might enjoy as much. For instance, it's worth studying a language, or history (which is very political) or social sciences like anthropology or sociology or even gender studies. Also, Asia-Pacific studies are worth looking into as well. It really depends on what sort of angle you'd like to look at politics.
Also, you can definitely get a career with arts (although if you combine it with commerce that might make your parents feel better) especially in the public service, or policy making. HR is also another area you could look into (especially with commerce). There are also heaps of jobs you can get just by having a degree of some sort. If you specifically want to work in international politics or similar (like for the UN or EU or something) it's probably advisable to get a Masters degree, and if you'd like to do research in the area, then you would need a Masters degree or higher.