GPA and SAT

I’m a international student applying to UPenn, NYU, and other competitive schools. I live in Japan, and we dont have any AP or Honors system, student volunteering, or weighted GPA. So I have pretty low GPA (we don’t calculate it here, but probably around 3.5), and not so good application. I don’t think my rec letters are that good either since all my teachers who wrote it are Japanese. Should I be worried? Or will they not consider that a disadvantage since I’m from abroad?

BTW my SAT score is around 1500(New SAT)

Colleges will view your transcript in the context of your school. If your grades are on the high side of the class, your odds are better than if your grades are in the middle of the pack. AO’s are experienced in evaluating international applicants.

By definition, you are at a disadvantage because you are an international student. At most selective schools, the admit rate for international students of roughly half of the overall rate.