Sentences with plural expressions can be ambiguous between a collective interpretation, where a group of agents acts together on a single object, and a distributive interpretation, where individual members act separately on different objects. Previous studies have identified developmental differences in both interpretation preferences and the use of distributive markers such as universal quantifiers: adults prefer collective interpretations, while children show no clear preference between readings; moreover, children struggle with distributive quantifiers in both comprehension and production, while adults reliably use them when needed. This study is the first to compare both comprehension preferences and production patterns across three age groups: Italian-speaking preschoolers, second graders, and adults. In a picture selection task, participants chose between collective and distributive pictures in response to unmarked, distributive, or collective sentences. In a production task, they described scenes depicting either collective or distributive actions. Results showed that all groups—including, surprisingly, preschoolers—accurately comprehended both distributive and collective markers and interpreted unmarked sentences as collective. However, in production, adults and second graders were more likely to explicitly mark distributive rather than collective interpretations, while preschoolers rarely used any disambiguating expressions. We argue that these findings reflect a developmental shift in pragmatic competence rather than in lexical knowledge, contributing new insights into the interface between semantics, pragmatics, and language development.