Not allowing me to claim child as dependant even though he only turned 18 in august of the 2018 tax year. turbo is saying I cannot claim because he was 18 on dec 31 2018?

[ton-hal]

I checked cra and I meet all qualifications to claim him. I believe this is a glitch in the turbo tax software. I am a single mother, I have claimed him for his whole life. no one else claims him as his father passed when he was a baby. the software is giving me an error saying I cannot claim as he was 18 or older on dec 31 2018 but this should not be an issue according to revenue Canada. please advise on how to proceed or if this glitch will be corrected. his birthday is august 2000

[TurboTaxKim]

Sorry, this is not a glitch in the program. CRA requirements are that the dependant for whom you are claiming the Eligible Dependant Tax Credit be "under 18". Although it does seem you should be eligible to claim this because your son was "under 18" at some point in the year, CRA uses the age on December 31st of the tax year.

CRA does not clearly state this, however there is a slight reference to the under 18 years of age at the end of the tax year rule in this CRA documentation about the Eligible Dependant Amount: https://bit.ly/2U4mL6A