Can sister claim right on property gifted through deed

State: Maharashtra My grandmother got land from her mother. My grandmother transfer property to by gift agreement to her son and grandsons. Then my father sold his whole portion of land to me using property sale deed agreement, I have paid him 20 lakhs rupees in agreement cash. All above transaction have done at government sub register office. Now my sister are saying it’s their ancestors land, So my father or my grandmother cannot sale or gift these land to me, they are demanding 25% of my land. Is my sister have any legal rights in my above land? Is above transaction look good? My father and grandmother pass away long back.