This sometimes comes as a shock to people claiming teenage dependents, but you lose the child tax credit in the tax year that the child turned 17 even if he turned 17 on December 31. That is how Congress wrote the tax law. Sorry. You can still get the $500 credit for other dependents. You do not get stimulus money for a dependent who was over the age of 16 at the end of 2020.
CREDIT FOR OTHER DEPENDENTS