Can I claim my child on my 2025taxes who turned 24 in December and was a full-time student during the spring semester only?

[DoninGA]

Since she is older than 23 you can only claim them as a dependent under the Qualifying Relative rules.  Under the rules the dependent's total income for 2025 must be less than $5,200 along with the other rules.

To be a Qualifying Relative -

1. The person cannot be your qualifying child or the qualifying child of any other taxpayer. A child is not the qualifying child of any other taxpayer if the child's parent (or any other person for whom the child is defined as a qualifying child) is not required to file an income tax return or files an income tax return only to get a refund on income tax withheld.
2. The person either (a) must be related to you or (b) must live with you all year as a member of your household.
3. The person's gross income for the year must be less than $5,200 (social security does not count) in 2025
4. You must provide more than half of the person's total support for the year.
5. The person must be a U.S. citizen or a U.S., Canada, or Mexico resident for some part of the year.
6. The person must not file a joint return with their spouse with the following exception -
You can claim a person as a dependent who files a joint return if that person and that person’s spouse file the joint return only to claim a refund of income tax withheld or estimated tax paid.

[Hal_Al]

There are two types of dependents, "Qualifying Children"(QC) and Other ("Qualifying Relative" [QR] 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.

Since your child turned 24 before the end of the year, he/she can no longer be  QC. So, we look to the QR rules to see if he can still be a dependent.  Student status not longer matters for dependency.  But, if you paid tuition or other qualified expenses, for your QR dependent, then you can still claim the tuition credit.