Studypoint

After 12th, you need to take SAT in order to be eligible to apply to a lot of major universities abroad. However, it is not compulsory. Some colleges do not require SAT scores. Some require ACT. But some require none of them. I would suggest you take SAT preferably in 12th grade or even after that as soon as possible and then look into individual websites of the colleges you want to apply to. To check if they accept TOEFL or IELTS. Both of them are English tests. some colleges ask for TOEFL and some want IELTS scores. If you don't know how to get started, attend some study abroad fairs.

Dear Shivansh,
2 LPA is not even sufficient to study in India, hence definitely you need the scholarships for Bachelor's. However, USA is the best destination to do BS in CSE. For this, you need to score exceptional good marks in GRE. Based upon your entrance score, class 12th marks and other achievements make your profile better for American universities.
Hope this helps.
Good luck.

Can you please elaborate BMAS, as there is no entrance exam for the same?

On which factors are you anylzing these countries for taking admissions?

You can apply for the examination under the lateral entry. Your score in the exam will get you the related branch.