Congratulations Ghanshyam,
You have achieved a good rank so you can easily get CSE in the NITs and the IIITs like NIT Rourkela, IIIT Allahabad and many more.
Even if you belong to general category you can easily enter the NITs AND IIITs
So you can easily get admission in various government engineering colleges.
You can also see the cut-off of the top NITs from the link given below.
https://engineering.careers360.com/articles/jee-main-cutoff-for-top-nits
I hope that you got this rank in JEE Mains as the above named colleges are for the JEE Mains aspirants.

Hello,

It seems you forgot to mention in which exam did you get 3504 rank. If you are talking about Mh-CET/JEE, then I would like to say that 3504 is a pretty good rank and you can easily get Computer engineering in good government colleges. Please mention the exam so that we can guide you properly.