Should I opt for full-time B.Sc in IT or CS or pursue the same through correspondence?

Always prefer full-time over distance. If you were working, I will suggest you distance but as a fresher, go with regular. No matter B.Sc CS or IT, what matters is how you are good in the subject.

Full-time degree in CS or IT is better because it has better learning opportunities along with access to college computer labs to practice theories learned. In full-time degree, you have access to teaching staff and fellow students for discussion and clarifications of doubts.