tataḥ pariṇate kāle
gāṁ putrāya gato vanam
tataḥ—thereafter; pariṇate kāle—when the time was ripe; pratiṣṭhāna-patiḥ—the master of the kingdom; prabhuḥ—very powerful; purūravase—unto Purūravā; utsṛjya—delivering; gām—the world; putrāya—unto his son; gataḥ—departed; vanam—to the forest.
Thereafter, when the time was ripe, when Sudyumna, the king of the world, was sufficiently old, he delivered the entire kingdom to his son Purūravā and entered the forest.
According to the Vedic system, one within the institution of varṇa and āśrama must leave his family life after he reaches fifty years of age (pañcāśad ūrdhvaṁ vanaṁ vrajet). Thus Sudyumna followed the prescribed regulations of varṇāśrama by leaving the kingdom and going to the forest to complete his spiritual life.
Thus end the Bhaktivedanta purports of the Ninth Canto, First Chapter, of the Śrīmad-Bhāgavatam, entitled “King Sudyumna Becomes a Woman.”
Link to this page: https://prabhupadabooks.com/sb/9/1/42