If your daughter turned 17 before the end of 2018 you cannot get the child tax credit for her. You lose that when the child turns 17. Instead, you get the $500 credit for other dependents. You can still claim her as a dependent.
https://ttlc.intuit.com/questions/1900923-what-is-the-child-tax-credit
https://ttlc.intuit.com/questions/4499708-what-is-the-500-credit-for-other-dependents-family-tax-cre...