Yes, obviously, one of the two major disciplines you’ll be studying is different. Communication vs Instrumentation. My suggestion however is that, at this juncture of your education, you neither know what communication is about nor know what instrumentation is about, (don’t judge based on the one or two chapters from NCERT) so since you’d decided to randomly bet on communications, you can give instrumentation out a try as well. In the end, it won’t matter much, it’s not as different as let’s say something like CSE and EIE would be.
All the best.