Adoption Carry-Forward Tax Credit error on Turbo Tax’s form? Adopted child turned 18 in Oct- TT is not allowing me to claim my carry-forward credit due to this. Help!

I adopted a special needs child 4 years ago. I am supposed to have a $19,500 carry forward credit to apply to my tax liability. My child turned 18 last October so Turbo Tax keeps telling me that I don’t qualify for the carry over credit this year, but I can carry it forward next year. Resulting in my refund being almost $5000 lower.  However, the IRS documents show that I am still allowed to carry-forward those credits until I hit 5 years and says nothing about an age out period to be able to claim that credit. Is this an issue I need to resolve directly with Turbo Tax or am I misunderstanding something here?