Usually, the main characters in anime are finely organized personalities. There are a lot of lyrics in anime. I don’t see anything terrible for a teenager. Anime is a very teenage genre. Often touching, vulnerable, beautiful, inspired.
Look at something. The same “Ghost in the Shell” (cyberpunk) or “Your name” (family).
The fact that her room is covered with posters and filled with figures … Well, she’s still a child. Why do you expect adult behavior from her? As for her friend with a “decent” room, IMHO, it’s boring and impersonal.
South Park is bad. Better to let Futurama or The Simpsons look. I’m serious.
What sits in the room is both bad and normal. Write it down somewhere. To dance, to draw anime, to the pool. Try everybody. Socialization is needed.
In general, you, IMHO, have a good child. With hobbies. Don’t crush it. By the way, people who work in the production of games earn very decent money (well above average). Take a look at hh.ru. And without gaming experience, they won’t be accepted into the gaming industry. This is just a note ..