Thats great that you are thinking about your graduation from right now but brother thats too early. You will need to tale the science field first of all in your junior college (11 and 12th) with PCM as your main subjects. Then you will neeed to give the JEE MAINS competitive entrance examination. And then on your merit score you can get into IIIT.

Refer to the website below for knowing more about the JEE Mains exam and alsso about the IIITs...

https://engineering.careers360.com/exams/jee-main

IIIT colleges of India - https://engineering.careers360.com/tags/list-of-iiit-in-india

JEE Mains exam cutoff for the same -

https://engineering.careers360.com/articles/jee-main-cutoff-for-top-iiits

Best wishes. Thank you.