Can I do M.Arch after B.Sc in interior design?

Unfortunately not because, for pursuing M.Arch. You must have 5-year B.Arch degree.

As per my knowledge eligibility for M.Arch is B.Arch. B.Sc in interior is not eligible for M.Arch. For more clarification, please visit NATA website.

Yes, you are eligible to do M.Arch after completing your B.Sc. And it is a good choice to do master's degree. Because of master's degree, you will get good opportunities in your career. And M.Arch is a good option to get a good job also. So, you can go through the same. Good luck.