I am already in America, and my English is still poor. I walked past God! Help! Thank you!

Take your time and don't worry too much.

If you think you will be afraid of making mistakes when talking to your classmates, you might as well try talking to the teacher first. [Personally, I think it's a good method]

In fact, there is nothing wrong with English, as long as others can understand what you are saying and what you want to describe. Language is used for communication. Why does it exist without communication language?

Language barrier is really not just a matter of speaking, so you can accumulate some common words, listen to others (preferably native speakers) and try to imitate them, so you can see your progress bit by bit.

You still have enough time to get better. Remember this, you shouldn't be ashamed of your accent, but practice it often. As time goes by, you will see how your English level has improved. :)