WHY DO I GOI WENT TO STUDY IN U.S/¶

To be honest, I didn't (go to[get to?] study abroad until I entered my university.

Not sure what you wanted to say but
To get to do something= to be able to/to could do something

So either:
I didn't get to study abroad until... = I wasn't able to do
Or just drop 'go to' to say you only went after university

If you use 'my university' it sounds as if the university is your property.

I could studystudied hard in English hard, so my English score was always good.

You don't need the second English here as it's already mentioned.

I can tell you why I like English: it's because m My parents went to study in the U.S, and they met there, and then finally they got married.

So I think this is my root of why I started to take an interest in English.

When I entered my university, my feeling changed.

It let me know that I actually wanted to study abroad, however I didn't have the courage to do so.

So I decided to go to America, and. I would like to speak English well and talk to people around the world.

WHY DO I GO TO STUDY IN THE U.S

In this very specific situation, “go” should be used with a bare infinitive. “To” refers to purpose and changes the meaning, requiring a change of word order.
https://www.usingenglish.com/forum/threads/163933-go-infinitive-or-ing-form

To be honest, I didn't gowant to study abroad until I entered my university.

I could studyied English hard, so my English scores wasere always good.

I can tell you why I like English: it's because my parents went to study in U.S, and theythe US, met there, and finally they got married.

So I think this is mythe root of my English.

It let me know realized that I actually wanted to study abroad,; however I didn't have courage.

Conjunctions like “however” and “therefore” cannot be used to connect clauses.

SoNonetheless, I decided to go to America, and I would like to speak English well and talk to people from around the world.

WHY DO I GO TO STUDY IN U.S.

To be honest, I didn't gowant to study abroad until I entered my university.

I could studyied English hardintensively, so my English score was always good.

I can tell you why I like English: it's because my parents went to study in U.S., and they met there, and finally they got married.

So, I think this is my root of English.

When I entered my university, my feelings changed.

It let me knowAfter they made their decision, I realized that I actually wanted to study abroad, however I didn't have the courage.

sounds better this way

SoNevertheless, I decided to go to America, ands I would like to speak English well and talk to people around the world.

I put "nevertheless" instead of "so", because above you said you wanted to do it, but you were scared, but "nevertheless" you decided to go to America.