Because, after coming to Singapore, you have to go to a government school for interviews and exams, including English, math and Chinese. If you pass the exam, the school can let you continue your study. You can apply for Secondary Two here, and you'd better enter Aauto Quicker class. The fast class in the middle school here is four years, and then you can take the O class, the slow class is five years, and then you can take the N class. As long as you can speak English, it is completely acceptable to take the second grade course here.
If you come back from Secondary Two in China, or from Secondary Three, it will take you a short time to adapt to Singapore, which is quite unfavorable for you to take the O-level exam. Then I have to take the N-level exam, which is not good for children from China who study better. Remember!
According to your present situation, if your English is ok, you can only study in Form 2 when you come to Singapore, and you must be downgraded. You will be several years older than the local children, so you have to adapt to the gap in your heart. If you can enter the courier class and pass the O class smoothly, then you are really a miracle. If you enter the class slowly and pass the N grade, you are two years behind the domestic children of the same age. Time, thinking about time will play an important turning point in your life.
Plan with your parents before you go out to study.
Wish you success!