I'm not saying that programming experience and training is not important, but 3d programming actually uses little of the more involved aspects of C/C++. Instead you will often be dealing with very simple data structures, functions and object models. The algorithms you will need to work with though, are usually based on horrendously complex math/3d concepts and if you don't understand these properly, you will have lots of problems. ie if you have a limited time to learn this stuff, start with the math first and slowly learn as much code as you need to implement the math. If nothing else, this will at least tell you right away if you even want to do 3D coding.

There really is no point in becoming a pro coder first and then finding that you suck at math so badly that you cant even do a basic modeller with your amazing programming skill.