Aviation

The cheapest flying schools in India are HM Aviation Private Limited, Flying Academy India, Government Aviation Tinstitute, Institute, National Flying Training Institute, etc.

Yes, you can, but firstly, you have to get the details of eligibility criteria.

Eligibility
Age
Minimum 17 years| Maximum 24 years
Other eligibility criteria
Candidate must have passed 10+2 from a recognized board and having a pleasing personality and good communication skills.

Commercial Pilot Training Course is always called the same no matter wherever you go. If you are planning for abroad than you should enquire for CPL DGCA course. Because ultimately when the License will come to India than it should justify Indian DGCA requirements for issue of the same.

Placements are typically fair, not too good and not too bad. If you do good at your course you can expect to get placed.

Your height and other parameters are absolutely perfect for the profile of cabin crew but I'm afraid eyesight of -ve 2.5 is a matter of worry.
Usually acceptable range is +/- 0.5. Still you should check with the hiring airline. Because eyesight parameters vary from operator to operator.

Rahul,
First, finish your class 12 and then if you are interested in doing your CPL training from any private club, you can apply anytime. And if you are looking for IGRUA, then the notification comes in the month of September every year.

IATA shall only provide you training. You will have to look for a job on your own. They usually do not provide any placements or jobs as such. The certification provided by them is acceptable at many places and it is also very well recognised. So it should not be too difficult to find a job.

You should be aware that the cost of CPL Training is dependent on the type of aircraft you choose to get trained on.
Cessna 152 - Rs.7000-8000 per Hour
Cessna 172 - Rs.9000-11000 per Hour
P-16 - Rs.15000-18000 per Hour, etc.
Any candidate who gets enrolled for this professional training requires to complete 200 hours of flying, in order to get his/her CPL issued. Hence the total cost including accommodation + food goes around 30-40 lakhs.