Re: beginner with no experience. Want to start to learn coding.
If you want to roll you own Linux Window Manager, you will have to learn C (and may be C++). But this doesn't need to be the first language you learn.
Python is a good programming language for beginners, but for what I have seen it's not very well suited to graphical UIs. In your case I would recommend Java, since it has a somewhat built-in graphical UI toolkit (Swing) with which you can learn the basics of object-oriented programming and UI programming.
Warning: unless noted otherwise, code in my posts should be understood as "coding suggestions", and its use may require more neurones than the two necessary for Ctrl-C/Ctrl-V.