Just me being negative ;)

This sounds like a very natural and casual statement!

I am reading a kKorean novel ancalled "Flowers for Algernon" right now.

I do Science'm majoring in Computer's major Science, but I started the college without any knowledge,. I though that even without knowing anything, it'll would be okay if I study hard...

I am reading a kKorean novel and “Flowers for Algernon” right now.

“Korean” is a proper noun and should be capitalized. You should also put quotes around book titles

I do’m trying to get a Science Computer's major, but I started the collegurse without any knowledge, I thought that even without knowing anything, it'lld be okay if I study hard...

1. “I’m trying to get” sounds better than simply “I do”
2. You should say “course” instead of “college”, since you’re just referring to your major, not your college in general
3. “It’ll should be used instead as you’re using the conditional tense

I know that 'someday' I will learn that, but... I want to improve faster.

“That” can be take out, as it sounds a bit redundant

I am reading a kKorean novel and Flowers for Algernon right now.

I do Sciencestudy Computer's major Science, but I started the college without any knowledge, I though that even without knowing anything, it'll of what I was getting myself into. I thought I would be okay if I studyied hard...

Everyone seems to know everything, whilen I don't even know what they're talking about.

I know that 'someday' I will learn that, but... I want to improve faster.

I'm really, really doomed.

I'm not sure about the word "doomed" here. It is a very strong word.

I do Scienceam majoring in Computer's major Science, but I started the college without any knowledge,. I though that even without knowing anything, it'll be okay if I study hard...

The correction is the standard way to say it.