This longitudinal study investigates metacognitive development in children aged four to six (N = 148; 74 girls; 106 White, 21 multiracial, 17 Black, 3 Asian, 1 Latino; collected in 2017-2019) compared to adults (N = 26, 13 women; collected in 2022). We assessed metacognitive monitoring and control using experimenter-elicited and self-generated responses in decision-making tasks. Children demonstrated reliable task monitoring by age five and performance monitoring by age six, only on self-generated measures. Children's choice patterns were driven by uncertainty until age six, when performance-optimizing patterns emerged. Cross-lagged panel analysis showed early monitoring abilities predicted later control, supporting the monitoring-drives-control theory. These findings illuminate the early metacognitive development trajectory, notably the transition from uncertainty-based to performance-oriented decision-making.