How do I know everything?

Computer Science major here,
It seems like everyone in my class knows everything already,
And they quickly absorb all new information.

How do I become like this?

You can't. Pico della Mirandola may be knew everything. That was 500 years ago. When Diderot and d'Alembert started their Encyclopédie it was already impossible to know everything. You can't know everything about computer science. You can't know everything about a particular field of computer science. Kill yourself or get over it.