Right to claim property of Maternal Grandfather

There's is an existing property from my Maternal Grandfather (deceased -30 years ago). There's is no official will in this case, so it should follow standard law of succession or inheritance, which is to my grandmother and her children. However my mother has relinquished her claim in that inheritance and signed off the property to her siblings. That technically restricts me from any claim to that property whatsoever. However my query is, since the property is not created by my mother,but only inherited from her father, does she have the right to relinquish my right to inheritance from the property, as I was not a minor when she had signed off her claim. Also now since she has already relinquished her right, do I have any legal right to claim my inheritance in my Maternal Grandfathers property.