Using examples from family letters sent to the Department of Education's Elementary Correspondence School (ECS) in the western Canadian province of British Columbia in the early twentieth century, this article discusses three potential problems or traps associated with concepts of agency in the history of children and youth. Following a brief discussion of the emergence of agency in childhood studies, it focuses on three approaches to agency that it is argued limit our efforts to demonstrate the contributions of young people to historical change: contributory, binaried, and undifferentiated approaches to agency. Investigating the ECS family letters through these three approaches demonstrates their limits while also pointing the way towards more productive pathways. By focusing on more nuanced interpretive strategies, such as empathic inference, structural and relational analyses, and explicitly theorising around the key concept of age, young people emerge more clearly as actors in history, not merely subjects of history.