I believe I have messed up on my child credit on my taxes cause it did not give me my child credit

Who mailed you a Schedule 8812? Was this an IRS notice requesting additional information?

The Child Tax Credit is available for each qualifying child under the age of 17. The Child Tax Credit is valued at $2,000 per qualifying child. However, in the tax year that a child turns 17, they no longer qualify for this credit and may, instead, qualify for the Credit for Other Dependents, which is valued at $500 per qualifying dependent. The Child Tax Credit itself may be nonrefundable first (reducing your tax liability dollar-for-dollar to the full amount of the credit or $0), with up to $1,400 refundable, which could increase the amount of your refund. The Credit for Other Dependents is nonrefundable only.

The credit is calculated based on your dependent information entered in the My Info section of your return. No additional steps should be necessary to have the credit entered on your return if you qualify. However, you may review the credit under the Deductions & Credits section of the software.

Child Tax Credit