Despite the paradigmatic shift towards participatory governance across a variety of socio-political contexts, children and young people remain frequently excluded from meaningful participation in educational policy processes. This contradiction between democratic aspirations and practice is particularly evident in music education, where institutional structures often limit student voice to consultation rather than genuine collaboration. This presentation will share findings from a doctoral study that explored how children's agency in policy co-construction can transform music education practices within Finland's Basic Arts Education system.Situated within the multidisciplinary field of child perspectives studies, this practitioner inquiry drew on developmental work research and cultural-historical activity theory to investigate two central questions: In what ways do children and youth collaboratively shape music school practices when their agency and decision-making capacity are supported? What organizational dynamics and democratic potentials surface through such participatory policy approaches?The study’s twelve-month formative intervention engaged 25 music school students (ages 9-15) across two extracurricular music schools, focusing on peer-group project planning and implementation with practitioner-researcher guidance. Data generation included video recordings of group lessons, student interviews, WhatsApp conversations between students and teacher, and researcher diary documentation. Analysis employed diffractive methodology alongside policy review of national curricular frameworks.The findings indicate that children's inclusion in music schools can be enhanced by supporting their agency through experiences of relevance, social connectedness, and capacity to act. This approach demands attention to both individual skill development and horizontal socio-spatial dynamics within students' musical activities, as their aspirations develop through relational engagement. Opportunities for students to impact meaningful decisions illustrated how individual needs interconnected with social relationships, with music-focused classes at the comprehensive school providing crucial peer networks and social support.The analysis showed that enhancing children’s inclusion demands moving beyond access and representation towards reconceptualizing the frameworks through which young people and their musical development are understood and administered. Although music schools have historically operated under linear advancement expectations aligned with professional training standards, policy implementations developed without direct child participation make their inclusion experiences increasingly arbitrary. Recognizing student agency as an ecological achievement requires fundamental reconsideration of how musical development is understood and facilitated. The study indicates that incorporating children's perspectives into music education can reconnect art's meaning-making potential with fundamental questions of human and social existence, disrupting traditional institutional hierarchies and opening new possibilities for relational music education.