You can start from the bottom up or the top down. You will need a good math background for bottom up work, but you could also try learning graphics by starting

You can start from the bottom up or the top down. You will need a good math background for bottom up work, but you could also try learning graphics by starting from a high level framework and getting lower in the stack. E.g, learn an open source 3D framework like three.js and build stuff with it. Once you get good building 3D scenes and apps, learn how to extend three.js with custom functionality. Then learn the low level WebGL APIs the three.js is built on top of and implement your own graphics framework. Since three.js is open source, you can learn quite a bit by just examining the code. You could also do something similar with the Godot Engine or any other open source 2D/3D framework.