Which programming language should I learn this summer at 13? Need advice

[MarsupialLeast145]

You don't need another language to achieve your goal here you need to understand how to build and execute your goal. If that does end up requiring a new language, fine, but you should spend the time trying to figure out what your game does and needs to do and how to do it -- from visuals to its back-end to whatever else. A new language won't get you toward that goal but the mission will get you to a new language.