I am about to immigrate, and I am very confused in my junior year. ..

It is unwise to transfer, because American universities won't let you be a senior, so if you try to transfer, you will probably still be a junior in the United States.

I don't quite understand the significance of rereading undergraduate courses. Is it a complete reapplication for undergraduate courses in the United States? In that case, you have wasted too much time, which is not worth it.

When can I get my visa next year? I suggest you go to the United States for postgraduate study after completing your undergraduate course. From now on, you can plan the progress of exam review and so on.

The most important thing is your visa. The visa officer can find out whether you have an immigrant visa, so if he finds out your arrangement, he won't give you a student visa of F 1, which is why you need a green card to enter the United States as a student.

PS, if you still study economics, you need to submit GRE scores; If you apply for business, you need to submit GMAT scores.