You need to score a minimum of 75% in your PCM first of all in boards. And then on your merit based score in either JEE OR CET will give you a seat in desired engineering college to pursue computer science engineering. If you want good government colleges then you will need around 185+ marks in JEE out of 300 and around 150+ marks out of 200 in CET. These will have physics chemistry and mathematics as subjects.

And then while pursuing engineering, you'll be introduced to all the software languages and subjects.

Refee to the site below for more detailed information.. Also tips are given to crack the exam.

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

https://engineering.careers360.com/articles/how-prepare-for-jee-main

https://www.careers360.com/courses/computer-science-engineering-course

Best wishes. Thank you.