Yes, the new law raised the age from 16 to 17.
The increased CTC is not retroactive to 2020. Rather, it takes effect for tax year 2021 (returns filed in early 2022).
To qualify the child must be UNDER the age of 18 as of 1/1/2022.
https://www.kiplinger.com/taxes/602431/child-tax-credit-2021-who-gets-3600-will-i-get-monthly-payments-and-other-faqs#:~:text=To%20qualify%2C%20the%20child%20must,head%2Dof%2Dhousehold%20return.