(3)Age requirements
(A)In general
For purposes of paragraph (1)(C), an individual meets the requirements of this paragraph if such individual is younger than the taxpayer claiming such individual as a qualifying child and—
(i)has not attained the age of 19 as of the close of the calendar year in which the taxable year of the taxpayer begins, or
(ii)is a student who has not attained the age of 24 as of the close of such calendar year.
(2)Student defined
The term “student” means an individual who during each of 5 calendar months during the calendar year in which the taxable year of the taxpayer begins—
(A)is a full-time student at an educational organization described in section 170(b)(1)(A)(ii), or
(B)is pursuing a full-time course of institutional on-farm training under the supervision of an accredited agent of an educational organization described in section 170(b)(1)(A)(ii) or of a State or political subdivision of a State.
but let's say the person is over the age limit. nevertheless, you may still be able to claim them as a dependent - qualifying relative if these tests are met
(d)Qualifying relative
For purposes of this section—
(1)In general
The term “qualifying relative” means, with respect to any taxpayer for any taxable year, an individual—
(A)who bears a relationship to the taxpayer your child would meet this test,
(B)whose gross income for the calendar year 2021 iis less than $4300
(C) you provided over one-half their support for the year
