I want game development-related job
This is just another thing to consider, but since it is your future career it is probably the most important thing to consider.
I can personally vouch for Nintendo DS, Nintendo Wii, Nintendo 3DS, Xbox 360, PlayStation 3, PlayStation Portable, PlayStation Vita, and Android all requiring Windows for development, and iOS requiring Mac OS X (I have been corrected on Android—it has kits for Linux, but it is the only one in this list that does). The only time I have ever even seen a Linux machine was the one day I worked at Morgan Stanley, which is clearly unrelated to video games.
Not only that, excluding mobiles (since you stated you don’t want to work with them), all current consoles, as well as development for Windows, are much closer to (or exactly) DirectX 11. It is no secret that the next Microsoft console will use DirectX 11, and PlayStation 4 will be as well (or rather extremely similar). These will likely still be the relevant consoles when you graduate.
Ultimately, as was said, you can learn OpenGL as a means of learning general rendering concepts, but you can do the same with Direct3D 11 and avoid having to relearn an API in the future. In other words you can learn the concepts and then struggle with the relevant API later, or you can just learn the concepts and the relevant API up-front.
Besides, as was also stated, OpenGL’s bind-to-edit mechanism is a headache and OpenGL is simply refuses to evolve, sticking to the mistakes of a somewhat naïve upbringing for the sake of compatibility, whereas Direct3D 11 is a recently fully overhauled API designed to match the way modern graphics hardware works, where backwards compatibility has been sacrificed in order to rid itself of design flaws of the past.
By now the choice should be fairly clear. And speaking from personal experience when I had to work on Mac OS X after having avoided it like the plague for decades: You get used to it.