Wait, the query is "Harley sin lil daughter is old enough." Maybe it's a typo for "Harley's daughter is old enough." So maybe the user is referring to a scenario where Harley has a daughter, and now the daughter is of a certain age, perhaps to do something, like join a group, start school, or perhaps something more specific. But since Harley Quinn is a character known for her chaotic behavior, maybe this is a hypothetical or fan fiction scenario.