In two studies, we examined the decisions of children (aged 6-12 years old) when faced with the choice between two options in a social-comparison dilemma: to affiliate with a group in which they outperform all others (i.e., being the best), or with an advanced group, at the cost of losing their primacy (i.e., being with the best). Study 1 (N = 179, MAge = 8.90, 56.4% female) examined children's choice when presented with a two-option scenario; Study 2 (N = 211, MAge = 9.42, 50.7% female) examined the same decision following children's experience of an actual task, while manipulating the children's relative position before the decision (by priming them to imagine that they were the best at the task, compared with a control condition, without manipulation). Results revealed a consistent developmental pattern, such that with age children preferred to join a group of leading performers, even if it meant they would not be the best. We examine the children's reasons for their decision, and their implicit theories of ability as possible mechanisms behind this pattern.