What exactly is school?

Hello, I'm 16 and I don't understand school.

What's the point of school and learning mostly unimportant knowledge that you'll never need in life?

A few subjects make sense, but after that I'm immediately confused again.

Subjects that don't interest me I just don't manage to learn.

About me :

I have depression and I'm working on coming to terms with myself and I don't need school because I'm going to repeat anyway.

But my family attaches great importance to it.

What is the insane meaning behind the concept of school, which I and probably many people don't seem to understand?

Is there any value in telling parents about this exaggerated topic?

Does it make logical sense to skip some subjects to take care of myself?

I didn't want to make this too ego-centered, but anyway, I just want to know what the meaning behind school is.

Does skipping make sense in this logical context?

I hope there were some logical questions from the text and I ask for personal experiences.