I am 20 years old this year. I immigrated to America this month. How can I go to their regular university?

Go to a language school for a class, and then take the TOEFL. If you have a high school diploma, high school grades and TOEFL scores in China, you have to take the SAT, which is the American college entrance examination. Then many schools require AP scores, and then go to some schools for preparatory courses or summer vacations, which can help you apply for universities. It's better to go to a regular university, with different experiences, and don't go to any messy institutions. Even community colleges are better than those educational institutions.