Both these fields CA and IIT are totally different, but according to my opinion, IIT will be the best option

CA is top choice for commerce students & IIT is for engineering students

For CA, you are required to have very good mathematical skills and business interest as well. And for admission in IIT you are required to have very good understanding of physics, Maths & chemistry.

If you interested in technology, then I will suggest you to go for IIT

IIT Colleges list

IIT Bhubaneswar

IIT Bombay

IIT Delhi

IIT Gandhinagar

IIT Guwahati

IIT Hyderabad

IIT Indore

IIT Jodhpur

IIT Kanpur

IIT Kharagpur

IIT Madras

IIT Mandi

IIT Patna

IIT Roorkee

IIT Ropar

IIT (BHU) Varanasi