Hello Paramjit,

I would like to tell you that to get admission in IIT delhi or any other IIT, you will have to clear JEE MAINS with a good score and then give JEE ADVANCED and if you have a good score then you may have a chance at IIT's.

As you have mentioned CS branch, it is one of the most sought branch by students thus it has a very high cutoff so you have to be in top 500 of India so that you have a chance at it.

I would suggest you to folow the careers360's link given below which has  adetailed explanation of JEE ADVANCED and tips.

The link for the same is:https://engineering.careers360.com/articles/jee-advanced-2019

Hope this helps and all the very best!