Learn English before American immigrants leave.

You don't need IELTS and TOEFL, but it would be better if you really have the courage. From now on, learn common American spoken words. When you arrive in the United States, you will still encounter various English obstacles, because of the local culture and the regional characteristics of everyday language. If you are one or two years younger, you will naturally feel that you are getting to know each other, including the local culture and English.

Only high school English can get by. I don't think there is anything wrong with a simple conversation. Increase your common vocabulary.