Yes, having maths you will be eligible for B.Sc CS/IT.

As far as the second part of your Question is concerned, considering the career scope and placement prospects in ths IT/Software/Services Industry, I would say you must pursue MCA from some of the Good NITs after B.Sc. CS/IT. You need to appear for the NIMCET Exam to get admission in NITs for MCA.

B.Sc CS/IT + MCA ( NITs) is the better combination, above B.Tech CS from Tier 3 Colleges. Of course, if you get admission in CS at some of the Good Tier 2 Engineering Colleges, State Engineering Colleges , Top Private Universities as well as Colleges like RVCE, BMSCE, MSRIT and many others in Bangalore and Hyderabad, near Tech Hubs of India, you may prefer them over the former Option of B.Sc. CS + MCA.