No it's always been that way for the Child Tax Credit. See,
https://ttlc.intuit.com/community/credits-and-deductions/help/what-is-the-child-tax-credit/00/25961
IRS publication 972 for Child Tax Credit, https://www.irs.gov/pub/irs-pdf/p972.pdf
Look at it this way: when they were born (even if on Dec 31), you got the full $1000 for the whole first year, So, you got 17 years of the child tax credit.
