American Family Act of 2017 This bill amends the Internal Revenue Code, with respect to the child tax credit, to: (1) make the credit fully refundable, (2) increase the amount of the credit and allow an additional credit for children who are under six years of age, (3) require the amount of the credit to be adjusted annually for inflation after 2017, and (4) require the Department of the Treasury to establish a program for making advance payments of the credit on a monthly basis.