What grade am I in Japan?

I completed my senior high school here in the Philippines, and I wonder if I study in japan am I going back to being a high school student? I also don�ft speak Japanese.

This page will explain what you want to know.
https://education.jnto.go.jp/en/school-exchanges/japanese-education-sy...

Senior high school (usually 16-18 y.o.) is beyond compulsory education in Japan. It means you need to take and pass an entrance exam to enroll in a high school.
The official curriculum taught in Japanese high schools is all in Japanese. So, it should be difficult to enter one if you are not at the native level or close in Japanese.

Your options would be
- To get higher education (this is sometimes easier as there are some courses that accept students without Japanese proficiency, which is almost non-existent in high schools)
- To work

@Duday

Did you graduate from high school? If so, I'm not sure why you wouldn't be interested in going to college. Are you and/or your family planning to move to Japan?

If you have already completed senior high school, even if it was in another country, I don't think you're qualified to enroll in a senior high school in Japan. If you want to go to school here in Japan, you need to choose a college of some kind.

Junior High School.

You will be accepted as First year Junior High School here in Japan.
There are Cities that has night classes too! And it�fs been offered to all ages.

When I started studying Nihongo because I want to get a Japanese Driver�fs License in all Japanese lessons at Driving School, I enrolled in a night classes Junior High School, they accepted me officially as First Year JHS. Because I said I didn�ft went to College :)
It was okay. After I passed my Japanese Driving License in ALL Take 1. I dropped the JHS night classes. Just like that. Hehe.

Btw, my Classmates are from different ages and walks of life. There are Koreans, Peru, Brazil and so on.

Some of them graduated JHS and proceeded Senior High!

My mom is actually in Japan already and she�fs planning to get us. I�fm already 17 years old, is it okay if I�fm still a junior high school with that age?

@Duday

17 yo. Yes, of course.

Inquire in your Mom�fs City ward. At your nearest Junior High School. In our City, the JHS is offering night classes too!

Speaking no Japanese puts you in a tremendous disadvantage and also burden your school. If you want to have any form of good education, you'd need to go to an international school.

This is a list of junior high schools with night classes.
https://www.mext.go.jp/a_menu/shotou/yakan/index.htm