Hi Aspirant

You should know the syllabus of Instrumentation engineering.Is is simmilar to Mechatronics?

ofcourse not.

If you can study the syllabus of instrumentation engineering then it is fine.If you have basic knowledge of instrumentation subjects then you will face no problems.Its good choice but if you don't know anything about instrumentation then really its a bad choice.

You should have taken  electronics (ECE).Read the post of which the link is pasted below.Your all doubts will be clear.

https://www.careers360.com/mechatronics-engineering-course

https://www.careers360.com/instrumentation-engineering-course

https://drive.google.com/file/d/1Sa9Msc8FKW2pdN1pzPB9xe09ppXbKjFR/view

All the best.