My daughter was not 18 years old at the end of tax year 2024. Why am I not getting the full $2000 child tax credit?

For the full child tax credit, your child must be under the age of 17. You can learn more here.

The child has to be under the age of 17 on 12/31/2024 to be eligible for the Child Tax Credit.  If they are age 17 or older then they are eligible for the Other Dependent Credit of $500.