Patience and self-control are important non-cognitive skills that are associated with favorable educational, economic and social outcomes. This paper provides empirical evidence to inform discussions on possible educational interventions to make children more forward-looking or less present-biased, by putting forward a way to identify self-control problems in children and exploring the role of commitment devices in mitigating such problems. We report results from an experiment that measures planned allocations, the demand for a commitment device, and actual choices in the context of chocolate consumption over two days. The experiment is conducted as part of a large field study on children's preferences, which allows us to correlate behavior with variables related to the subjects' socio-economic background and educational environment, as well as preference parameters elicited through other tasks and surveys. We find a large demand for commitment among children. In addition, we identify important correlations between patience, commitment demand and time inconsistency, as well as student-specific personality traits and outcomes such as school success.