The reason why i chose PHP is the amount of content you can find on the internet easily.
As you quoted being a beginner, i think a more mature language would be better. And that's also another reason for following with PHP.
Python is simple and "mature", but it can be a bit hard to understand if you are a beginner. Python relies on heavy abstraction, and that's the reason behind it's simplicity. Python is an "easy to play, hard to master" language, i never recommend it to beginners. Also, one [maybe personal] reason why i don't like to use Python as back-end is: Python is very data-focused. So if your app has focus on business logic, Python wouldn't fit very well. And with that becomes an advantage, if your app has statistical focus, being data-focused or something like that, Python has huge advantage among all other languages due to many great tools the community has built.
About Node, it's like PHP, but less mature. It's as easy as PHP to find tools that can help you, for example, to abstract the database-connection's logic. But to find architectural-focused content, more advanced concepts, it's a lot harder. While that, Laravel's community, for example, has a lot of materials that involves those concepts.
Still, if you are really a beginner, i don't recommend using Laravel with PHP. Do things on plain PHP first, understand the reason behind using frameworks and Laravel's motivation.
Also, consider a strong-typed language first, those are considered more didatic, but less flexible.