during calendar year 2019. (d) Effective date The amendments made by this section shall apply to taxable years beginning in calendar year 2019. 7. Extension of child’s benefit for full-time post-secondary school students under age 23 (a) In general Section 202(d)(1)(B) of the Social Security Act ( 42 U.S.C. 402(d)(1)(B) ) is amended to read as follows: (B) at the time such application was filed was unmarried and— (i) had not attained the age of 18, (ii) was a full-time elementary or secondary school student and had not attained the age of 22, (iii) was a full-time post-secondary school student and had not attained the age of 23, or (iv) is under a disability (as defined in section 223(d)) which began before he attained the age of 22, and . (b) Definition of full-Time post-Secondary school student (1) In general Section 202(d)(7) of such Act ( 42 U.S.C. 402(d)(7) ) is amended— (A) in subparagraph (A)— (i) by inserting and a full-time post-secondary school student is an individual who is in full-time attendance as a student at a post-secondary educational institution before , as determined by the Commissioner