We analyze the identity trajectory of a single case study, Cassidy, within the physics community. We focus our analysis on two settings in the physics community: an undergraduate research experience, and undergraduate coursework. We use video data from three interviews (spanning roughly fifteen months) to longitudinally analyze shifts in participation. We discuss Cassidy's experience through two constructs: "normative identities," Cassidy's sense of the valued roles within physics, as well as "personal identity," who Cassidy is within the physics community and the extent to which she aligns with "normative identities." In attending to shifts in the alignment between personal and normative identities, we identify several "entry points," or salient events that open up new opportunities for participation.