See if you want to do your bachelors in USA after class XIIth, then you have to give SAT if you want to enter any technical field. Once you give SAT, the gates of very good colleges open for you. In US colleges, you'll need to produce some proof of your co-curricular activities in college, any kind of social work that you might have done. If you do these nicely, you'll surely get in.

Hope I have answered your question. All the best!