Guidance about school marks, sat, scholarships and in general an idea and experience of studying abroad

First all let me start with my 11th marks. I will be moving from 11th to 12th and I guess I will scoring above 80%, do the colleges aborad see my 11th scores, do they also see my 10th scores and below(10,11,12 are considered high school outside india atleast in the us)?

I would be going for maths or cse honours in college. In some colleges in india and aborad double major on those subjects are there so its an option too.

I am thinking if giving SAT a try this march as I recently got to know about it. What are the subjects in SAT or are there subject choices in SAT?

my_qualifications: I have some co curricular achievements though they are pan india based. Will they help?

Do the shcolarships and financial aid depend on your co-curricular achievements or academic or both. Please do tell me on this.

Lastly, the few people I asked about studying abroad have been telling me not to study thought they have not studied abroad, the reasons were change of environment and fees but I guess thats a given still if anyone can give a first person experience of studying abroad for college