According to the tradition of the Church, the Theotokos was brought to the Temple at three years of age, where she was consecrated to God and spent her days until she was fourteen or fifteen years old; and then, as a mature maiden, by the common counsel of the priests (since her parents had reposed some three years before), she was betrothed to Joseph.
Apolytikion in the Fourth Tone
Today is the prelude of God’s pleasure and the proclamation of man’s salvation. The Virgin is clearly made manifest in the temple of God and foretells Christ to all. Let us also cry out to her with mighty voice, “Hail, fulfillment of the Creator’s dispensation.”
Kontakion in the Fourth Tone
Today, the most pure temple of the Savior, the precious bridal chamber and Virgin, the sacred treasure of God, enters the house of the Lord, bringing the grace of the Divine Spirit. The Angels of God praise her. She is the heavenly tabernacle.
From www.goarch.org
Christians should be thankful that the Virgin Mary gave birth to Christ, because this birth of Christ resulted in man's salvation.