Introduction ( About me )

Now I'm 16 years old.

The "now" doesn't add anything here, it's better to leave it off

I'm studying in a high school student in Vietnam.

Edited to sound more natural

I'm livinge with my family: my parents and my eolder sister.

"older" fits better than "elder" in this context

In school, I'm very interested in Mmath, IT and English.

IT and English need to be capitalized, but not math

BesidesOther than that, I don't like physical education classes because I'm very bad atin this subjectat area.

"Subject" is a better descriptor for something scholarly and specific (like math and English above)

UntilFor now, my dream is to one day I will become a game programmer ( because I like games anyways, even though I guess that it's kinda of hard to do it :)) ).

"Until now" implies that it was your dream before, but you changed your mind. If it is your current dream, "for now" works. Also, "kinda" is slang so it's fine to use casually but you don't want to use it in school or professionally. The correct equivalent is "kind of"