My father purchased a property in my name when I was 16 yrs. Now I am a major and my father expired.

My father purchased a property in my name when I was 16 yrs. Now I am a major and my father expired. My step sisters are contesting that the property is purchased with my father's income and I was only a nominee and are demanding a share in this property. Is it valid by law. Are they entitled for a share in this property purchased by my father in my name when I was a minor.