Parent-child discourse in family settings provides insights into children's language socialization. In her seminal work on language socialization, Ochs (1993) argues that social identities are essentially constructed by verbal performance and the display of social acts and stances. This paper presents a single case analysis of a family dinner involving a three-and-a-half-year-old child, C, and her parents, M (mother) and F (father), interrogating how C asserts her identity, or resists those imposed on her, by "going categorical" (Stokoe, 2012) when counter-disciplining her parents. This analysis shows that when constructing her category membership, C appropriates her parents' voices and proffers her incumbency in the 'adult' category. The article concludes that the child appropriates adult language to claim power and to subvert the power asymmetry of the parent-child relationship, while the parents invoke duties and obligations associated with the categories 'parents' and 'children' to reinforce the power asymmetry of the status quo.