I want to apply for US college but I don't know how to get start???

Good Afternoon, Yu-Sheng Liu.

It's pretty clear that you have a very strong desire to become an astronaut, or maybe pursue a career in aerospace. To be an astronaut, you need to meet certain qualifications. Below, I am attaching an article with the requirements to be an astronaut for NASA ( The US' space agency) ( I am attaching links to relevant articles, so you can get more information)

How to be an astronaut:

https://www.space.com/25786-how-to-become-an-astronaut.html

You can plan your studies accordingly. But remember, don't ever give up in your dreams!

Now, you want to study in the US. First, talk to your family about your plans. Second, research opportunities to study abroad with your local university in Taiwan. See if your local universities have programs that allow you to study in the US. If they offer such opportunity, let them guide you.

If they do not offer such program, use the Internet to research how you can apply to universities in the US. I am attaching an article that addresses the application process for prospective international students (you).

Study in the United States:

https://international.collegeboard.org/prepare-to-study-in-the-us

If you read the entire article, you'll note that it says to take the SAT. However, there is an alternative test called the ACT. You can take either one or both. It's up to you. They have equal standing in admissions. I recommend you to take a practice test of both the SAT and ACT, and then decide which one you are going to take.

Now, you probably have to pass the TOEFL, which is an English test. I recommend you practice your English as much as possible, turn on English captioning on movies and Youtube videos. Or even better, watch them in English with the captions in English. Set your videogames in English. Talk with someone who speaks English. Learn English grammar.

Don't feel discouraged! There are thousands of  international applicants that are accepted to US universities! If you put the right amount of effort, you can do anything you want!

Relevant pages:

International US School search:  https://www.internationalstudent.com/school-search/usa/

How to apply to US schools as a foreign student: https://www.timeshighereducation.com/student/advice/hoping-apply-us-university-foreign-student

Scholarships for International Students:

https://www.topuniversities.com/student-info/scholarship-advice/international-scholarships-study-us

I wish you luck!! Follow your dreams!!