Python is not officially supported by Godot. There is a side project out there that tries to make it work, but using it would not be a good idea for a beginner.
People say to learn Python because it is relatively easy to learn (at least compared to many other languages), and there are a great number of resources out there for learning it. You can choose from videos, books, online courses, etc.
Languages are less important than understanding the basics concepts of programming,. Once you understand the basics, you'll find that languages are pretty similar. GDScript, which is Godot's built-in scripting language, is modeled after Python, so it looks very similar and will be familiar to a Python programmer.