Why did Mary stay on earth after the Ascension?

This delay was a great consolation for Christ’s disciples. It took nothing from the Mother, and it brought remedies of salvation to the world.

The Lord Jesus desired that, after his return to the Father, the Apostles might enjoy maternal assistance and education. Although already instructed by the Spirit, they still had to learn from the one who gave the world the Sun of righteousness and made the source of Wisdom spring forth for us from her immaculate womb, like a virginal meadow.

Finally, in its admirable goodness, Providence wanted the primitive Church, who no longer saw God present in our flesh, to be able to see his Mother and be consoled by this loving sight.

St Amadeus of Lausanne, Cistercian Abbot (1110-1159)

Homily 7: The death of the Virgin and her Assumption