I would suggest you start by learning C++ - if you haven't had any experience coding. If you have some coding experience, it would be a quick refresher to go through the basic topics, a few syntax differences etc. But then, it is learning and understanding important concepts of C++ like memory management, inheritance, polymorphism etc.
I would also suggest you take a look at Handmade Hero by Casey Muratori. Make sure, you see the "Intro to C" section too, where he walks you through debugging code using Visual Studio's debugger. Debugging code is a very important part in game development, which helps you understand how your code exactly works.
Hope that helps you.