IIT

IITs and NITs do not offer degree courses in mechatronics.

Diploma holders in engineering are eligible to appear for Joint Entrance Examination(JEE) conducted by IIT for admission in engineering at IITs and other engineering colleges.

In which field you are interested? You can choose either engineering or medical, so try to clarify your position, and secondly, placement does not only depends on your academic records. It mainly depends on your knowledge of the subject. IITs and NITs are the best brands in India, and also play an important role in shaping the future, but employment does not depend only on brand, it only depends on your capabilities.

Hello,
By qualifying JAM Test, candidates can apply for:
1 M. Sc (Two Year)
2 Joint M. Sc. - Ph.D
3 M. Sc - Ph.D Dual Degree
4 M. Sc - M.Tech
5 Post - Bachelor Degree Courses at different IITs
6 Integrated Ph.D Courses at IISC
For more details visit here - http://entranceexaminformation.blogspot.com/2016/07/iit-jam-entrance-test-queries-most.html
I hope it will help you.
Best of luck.

Admission at both is based on JEE Mains and the seats at IIST are just 20. Take a look at for all requirements
https://www.iist.ac.in/admissions/undergraduate
You can try for IISER/ NISER for an integrated degree.

Your language clarity, intelligence, workshops conducted by you, idea about your field, your confidence level. These types of qualities will be the parameters to get you selected in the campus interview.