Composed 1629" -- whether or not that's actually true, and there's some controversy about that -- but nonetheless, the subtitle announces to all who know John Milton that the poet was twenty-one years old at the moment of its composition and that he had therefore just reached his majority.

作于1629“-不管它是否属实，尽管对此也有一些争议，但它向所有知道他的人宣告,诗人创作这首诗时只有21岁,因此他已经超过了多数同龄人。

耶鲁公开课 - 弥尔顿课程节选