Adolescents are the decision-makers of the future, and as educational research shows, behaviors, habits, and attitudes established at young age strongly shape behavior in adulthood. Therefore, it is important to understand what factors shape young people's climate-relevant behavior. In this study, we examine how information about peer behavior affects adolescents' perception of prevailing social norms and own decision-making. Experimentally, we manipulated whether adolescents received information about other young people's (lack of) support for climate protection, operationalized as a donation to a CO2 offsetting scheme. We find that empirical expectations shifted for all age groups when the information revealed that peers donated nothing or only small amounts. Donation behavior and the normative assessment, however, changed only in the younger age groups. Our study illustrates the caution that must be exercised when others' behavior becomes visible or is deliberatively made salient in order to induce behavioral change, especially among young individuals.