Late enrollment in introductory computing is common yet consequential. Analyzing two offerings of a course{} course (Term 1: $n{=}204$; Term 2: $n{=}79$), we find sharply elevated failure rates for Week~4 enrollees (Term~1: 41% F; Term~2: 100% F) versus on-time peers (Week~0 failures: 10% and 2%). These outcomes coincide with markedly lower engagement in support resources (office hours, exam reviews). While some subgroups (e.g., URM late enrollees) show pockets of resilience, late international and late female students experience steep declines. Results suggest late entry beyond Week~2 in cumulative, fast-paced courses is a high-risk policy point, and that structured catch-up and mandatory early support are critical.