I suggest C.
Python is great for jumping in and getting simple flax done, its best used as a scripting language.
C++ is just too broad to start out with, and the benefits of that complexity are often unused.
C is has a very small featureset. That means its easy to learn in its entirety, and everything after that is learning how to use it. It also means you'll be doing your own boilerplate code. You've got to put in a bit more work up front.
Also once you're comfortable with C, you can expand to C++ if you desire.
For a compiler i suggest tinycc. its small, fast, simple and portable. And for a text editor i suggest sublime text. It's...its just amazing.,
If you want something a bit more visceral, quakec will teach you a lot about C, and bypass a lot of the difficult setup. In addition, its for quake modding, so you can make a quake mod and see the results. A whole new set of frustrations, but it really helps take some of the abstractness out of programming so you can get your head around it.