Feminism is based in a sense of the recognition of the inherent dignity and equality of men and women.  Fighting for justice is certainly not based in envy. 
As a son, I doubt that you knew everything that your mother felt and thought. I don't know how old you are and don't know the circumstances in which your mother lived.  If she was content and satisfied with her life, then good for her.
The fact is that, historically, there has been much discrimination against women.  Feminism fights for the end of this discrimination.  How can that be wrong?