B.Tech Mechanics

First of all, will you be specific and what do you mean by saying "campassing in the plea”?
Other than that, search for institutes where the criteria is 50% marks above, since your +2 marks is 57%.
Also, there are organizations where candidates with 50% marks and above get a chance to be recruited.

The placements for Amity-Kolkata is good as far as I know because many of my seniors have been placed in very good companies like Delloite, Indusland Bank, ITC, etc.

Amity-Kolkata is worth to do B.Tech mechanical and automation. But there are some subjects which are not needed but you still have to study them too. The best part is that you even have a foreign language i.e; French or German. You can opt for any one of them. And regarding placements, there are many peoples who have got placed in very good companies for ex-companies like ITC, Glenmark, Deloitte, Indusland Bank and more companies.

Hello,
If you want to explore more in the core field, the best line for you would be operations.
You can explore more on how in reality things work in an organisation at ground level.
In case you didn't like engineering, marketing can be the next promising field to dive into.
Good luck.

Following are some of the popular most specialised fields, on which one can pursue and get a M.Tech degree:
Aerospace Engineering
Chemical Engineering
Civil Engineering
Computer Science and Engineering
Electrical Engineering
Electronics Design and Technology
Mechanical Engineering
Metallurgical Engineering and Materials Science
Petroleum Geo-Science
Transportation and Infrastructure Engineering

You can't apply for APEDCET as you are still doing your graduation.