"I think he made an error filing for our 18 yo that was still in HS. "
You do not mention specifically what error you think was made regarding your 18 year old. But the fact that the child was still in high school would not affect eligibility for the child tax credit, if that is what you are thinking. The child tax credit rules were different for tax year 2021 -- and only for 2021-- in that you could get the child tax credit for a child who was younger than 18 by the end of 2021. If your child was 18 by the end of 2021, he was not eligible for the CTC even if still in high school. If he was older than 17 at the end of 2021, you could only get the $500 credit for other dependents when he was claimed as a dependent on your tax return.
Look on line 19 of your 2021 Form 1040 to see if you got the $500 credit; if he was younger than 18 at the end of 2021, you should see the child tax credit on line 28.
Or....do you think there was some other error? As others have commented, if the tax preparer made a mistake, the tax preparer should take care of amending for you at no extra charge.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
