Are information technology and CSE different?

There is no huge difference, but yes it is different from your 3rd year of B.Tech. In IT, it is all about Software, in CS it all about Sofwtare + Hardware + OS core. So, choose the same as per your interest like in software/programing language or in IT infra like network/server/Operating System etc

Yes, both are different beaches but the total subjects in B.Tech are differ by only 3 to 4. Remaining subjects are common in both. All the best.