Hey,

Basically for admission into the Masters of Arts in Psychology you will need to have graduation in Psychology field or should have studied Psychology as one of the main subjects with 50% aggregate from a recognised institute.

If you meet this eligibility criteria then only you can go for Masters in Psychology, otherwise you will be marked as ineligible. As you are commerce field student, you must not have studied this subject, so, you cannot get admission into MA in Psychology.

Know more about it over here: https://www.careers360.com/courses/psychology-course