You need to set some goals. What do you actually want to learn and what do you want to do with what you learn?
Do you want to make plugins for your server for fun? Then start learning amxx scripting, coding snippets/tutorials section is probably the best place to start. Check these tutorials:
https://forums.alliedmods.net/showth...awnProgramming.
If you want to apply the skills you will gain for other things besides just coding then you should consider learning a mainstream programming language.
python is easy, but will probably set some unrealistic expectations for you and when you move to other languages you will have a harder time adjusting.
In my opinion, and this is just an opinion, starting with C is the best way because it will teach you a lot of things that are not apparent in a language like python. You'll learn the basics of programming, you'll learn how memory works thru pointers, how to be responsible while programming and cleaning up after yourself plus you'll have to implement your own data structures and get a better feel for how they work/when to use them. It will be harder than python, that's for sure, but it will pay off.
Keep in mind that you can write C code in C++ with very few(or no) changes. C++ expands on C so it's not like you are wasting your time learning C and then having to start over with C++. If anything, C will give you a very solid base to understand the extensions that C++ provides: object oriented programming, templates, smart pointers, the standard template library, etc.
Lastly, I want to mention that learning the right way to think when trying to code and solve problems is the most important thing. You can do that with either pawn/amxx scripting or any other language, as this is language agnostic.