I have desire to learn shade writing, how do i start?

I am really curious about shade writing. I would like to learn this for production level, either for movie or games.So far, i have been modeling, hard surface and characters. I really want to do also, texturing and also creating shaders/materials. 

But, i am not sure how to even start. I never code in my life,i have no idea what engine should i use, what programming language to learn, and mostly, what theory or physics or whatever math it is involved in this. 

Give me some advice, suggestions, books etc, to start.