Information Technology

Yes, you can pursue CCNA. As per my knowledge, first, you have to do CCNA certification. There are many training institutes, which offer CCNA. I always recommend Koenig-Solutions.com for IT Course. To Know more about CCNA, go through below mention articles:
https://www.codementor.io/michaelwarne28/best-approach-to-study-for-ccna-certification-8clxso4zh
http://koenig-solutions.tumblr.com/post/151693925567/ccna-ccnp-collaboration-certificates-what-you

Hello Jake,
The major difference between both these field is that IT deals with the application of computing technology to real life processes, while, Computer Science deals with the science that facilitates these applications.
To make it short and simple, Computer Science is the creation of software and hardware by using different programming skills. On the other hand, IT is just the selection of the proper software or hardware for the task.
You may also refer to the link mentioned below:
https://www.shiksha.com/b-tech/articles/comparison-between-engineering-branches-cse-and-it-blogId-8490

Computer science engineers are involved in many aspects of computing from the design of individual microprocessors, personal computers and supercomputers to circuit designing and writing software that powers them.
Information technology deals with the use of electronic computers and computer software to store, protect the process, transmit and securely retrieve data. IT professional perform a variety of tasks that range from installing applications to designing complex computer networks and information databases.
Bith the branches are good, take the branch in which you are interested.

Yes, actually to appear for UPSC exam, the minimum qualification required is a Bachelor's degree.

Yes, you can. You can take admission in IGNOU Which is one of the prestigious institutions in India.