CBSE 10th

Now you are doing 12th and you are asking for PG courses after 12th you have to do graduation first. IIM admission is totally based on your CAT score, your interview weightage and maximum 20% from your previous education, so next step after 12th should be you will get some good government college. You can get admission on merit basis it will give you the great help in PG admission also and start your preparation for CAT level exam.

Eligibility for this course is to pass both class 10th and class 12th with the set criteria of percentage, so you can apply for this course after class 10th.

With your great profile, you will surely get admission in a Canada university, But, a greater IELTS band will result in better University options.

With class 10th and class 12th score less than 50 percentage, it will be less likely that you will be admitted in a good B-School due to the criteria being set at 50.

Hi Reshma,
Candidates with minimum 55% aggregate mark in maths & physics are eligible to apply for the course. https://www.shiksha.com/careers/pilot-91.

Yes, you can go for merchant navy after class 10th. But, if you are married, you should not opt for merchant navy job, as it is not a permanent job. You can be fired any time. Merchant navy is a private job and the age criteria is between 17 years to 21 years.

Hi,
You can refer to this article for guidance https://www.shiksha.com/aviation/flying-pilot-training/articles/career-in-commercial-flying-all-you-need-to-know-blogId-13472.

Apply in IITs. You may land in one of them.

Yes, you can sit for CAT/MAT/XAT. Though, it is bit difficult to get seat in IIM Ahmedabad (as they focus on career), you can get admission into other good colleges.

No, that's not possible, minimum eligibility is 10+2, check out the details below:
https://www.shiksha.com/university/north-eastern-regional-institute-of-science-and-technology/nerist-entrance-exam.