Can B.com or any other Commerce related courses be selected, though she has done Maths & Science Group in +2 [ie 11th and 12th]? Is it compulsory to take Commerce group in +2 to go for B.com?
Yes. She can join Commerce stream after clearing her 12th Science.
There is no compulsion to do only Commerce in 11th and 12th to take up B.Com or any commerce related degree for graduation.