Dear Souvik,

It is nice to know that you are interested to pursue an undergraduate program in the US. You can apply for undergraduate after you 12 class. Till then, I suggest work on your CGPA, take up an extracurricular activity, keep yourself interested in different subjects.

You can also practice the SAT and see that you score well. Also, you will need to prove your English language competency with tests like IELTS, TOEFL etc.

The top 11 universities for computer science according to Times Higher Education ranking are:

Do revert if you need more information.

Best wishes