expression, ichidan verb
Idiomatic expression literally meaning 'the shoulder tucks come out', referring to the removal of shoulder tucks from a child's kimono when they reach adulthood. Used figuratively to mean coming of age or becoming independent.
See also: 肩揚げも取れる (かたあげもとれる)
彼女は肩揚げが取れて、立派な大人になった。
She has come of age and become a fine adult.
When you reach the age of coming of age, you start thinking about your own path.