CBSE 12th

Yes, you can do BCA after 12th commerce but you have to face some problem in mathematics because in BCA, mathematics is a compulsory subject.
But in some colleges, you don't need to study mathematics.
And it is my understanding that it is good for you to select a good college for BCA, otherwise, it will ruin your future.
Best of luck.
God bless you.

You need to take GMAT if you want to get a good college abroad with maximum packages and scholarships. If not, IELTS is an easy option but it doesn't offer many options.

For B.Tech, you have to compete in the competition for B.Tech or any other UG admission.
For any other query, please feel free to ask.

You scored well in JEE Mains, in order to get admission in NIITs.

From which stream you are?

U can do maths honor.