Daughter finished high school early (Nov 23), but graduation date was May 30, 2024. Is she still considered a student until graduation?

Q. Is she still considered a student until graduation?

A. Probably not, if she didn't actually attend any classes.  But it may actually depend on the details. Was she awarded a diploma in November 2023 and May 30, 2024 was only a ceremony. Then, No.  Was she considered, by the school, as "enrolled" until May 30; then probably yes.

But, as @xmasbaby0  indicated, if she was under 19, on 12-31-24, it doesn't matter.

There are two types of dependents, "Qualifying Children"(QC) and Other ("Qualifying Relative" in IRS parlance even though they don't have to actually be related). There is no income limit for a QC but there is an age limit, student status, a relationship test and residence test.

A child of a taxpayer can still be a “Qualifying Child” (QC) dependent, regardless of his/her income, if:

1. He is under age 19, or under 24 if a full time student for at least 5 months of the year, or is totally & permanently disabled
2. He did not provide more than 1/2 his own support. Scholarships are excluded from the support calculation
3. He lived with the parent (including temporary absences such as away at school) for more than half the year