Using data from a large-scale field experiment, we show that while there is no gender difference in willingness to make risky decisions on behalf of a group in a sample of children, a large gap emerges in a sample of adolescents. The proportion of girls who exhibit leadership willingness drops by 39%, going from childhood to adolescence. We explore the possible factors behind this drop and find that it is largely associated with a dramatic decline in ‘social confidence’, measured by willingness to perform a real effort task in public.