Even though the schools/ colleges in the US have their own priorities in selecting applicants (like the merit obtained in the SATs or ACTs), they do take into consideration your performance in class 9, 10, 11, and 12. Since three of your classes are already over, you should focus really hard to score better in class 12. These are some of the steps you need to follow:

1. Research and finalize the schools that you want to apply to, and which subjects you are willing to study. If Ivy league colleges are your choice, apply to as many colleges as you can, keeping in mind what really sparks your interest and passion.

2. Request the schools for their application forms, fill them out and submit them before the deadline. The applications are usually filled in the months of October- November of the previous academic year . This means that if you want admission in 2021, you must apply in the year 2022.

3. Most schools abroad take into consideration your SAT and ACT marks. If your school of college does, check it out. You will have to give such exams and score good. Appear for the standard English language tests like the TOEFL or IELTS. Only if you score well, will you be accepted to institutes abroad. You have lost some time, but don't worry. If you study hard enough, this will be easy.

4. Obtaining a student visa will be your next step.

5. Prepare your essay for application (you will get instructions from the school you have applied to)

6. Gather letters of recommendation from the staff at your current school.

7. Make sure to check out the scholarships offered, as studying abroad can be very expensive.