Yes you are eligible for pgdm course by NISM.

To be eligible for Pgdm course by NISM, the eligibility criteria is as follows:

Minimum qualification

A bachelor's degree from a recognised Indian university or equivalent with a minimum of 50% in aggregate with the exposure of mathematics at 10+2 level.

Age 

There is no age limit for the programme, but it is desirable that the candidate is below 30 years of age.

Let me know if you require any further information..

Good luck!!