A lot of what I found leaned toward after puberty, the person became more adult-like and made their own decisions, instead of following orders. They became uncontrollable.
But here are some other possibilities, relating to other things we have researched, such as Hathor, the Order of Denderah, and other cults:
Greek Goddess Artemis is the Goddess of the moon and of the hunt, and the twin sister of God Apollo. Artemis is an ancient goddess, even in 700 BC she is worshipped as the mistress of animals. At the temple of Artemis at Brauron, near Athens, noble Athenian maidens called bears became members of her cult when they reached puberty. The Artemis in a deity form with many breasts is worshiped her as symbols of fertility. Artemis is also orgiastic goddess, in whose honor men and women performed phallic dances. At Delphi, the Artemis goddess led the dances of the muses and graces. Artemis is also a bearer of light. Many of the myths that surround Artemis applied to Diana, the Roman goddess of woods, forests, and the moon, which is also the protector of virginity. Her name comes from Diviana, ‘the shining one’.
Link here
Of course, the Gnostic Mass popped up...this had a lot to do with a ceremony, and it was speculated this would have been the ceremony for Bree to perform. The link for information on that is here: http://www.williamblakeoto.org/15.htmlQadishtu - On the one hand, there was the custom that every girl on reaching puberty had to give up her virginity in a sacred ritual context rather then a profane one before she could be wedded; she had to give herself in the sacred enclosure of the temple to any stranger who made a symbolic offering and invoked, through her, the Great Goddess. On the other hand, there were temples with an established body of temple slaves for the service of the goddess. These priestesses practiced a form of worship that the modern world called "prostitution." The mystery of carnal love was celebrated not in a formal and symbolic rite but in a magical, operative rite, to nourish the current of psychism which manifested itself in the presence of the goddess and, at the same time, to pass on to the men who copulated with the priestess the goddess’s influence or virtue as in a sacrament. These young women called "virgins" (parthenoi hierai), pure ones, or blessed ones (qadishtu, mugig, zermasitu), were deemed to embody the goddess and to be the "bearers" of the goddess, from whom, in their specifically erotic duty, they took their name, Isharitu. The sexual act thus performed had both the general function proper to sacrifices intended to invoke or revive divine presences and a function structurally identical with participation in the Eucharist. Ritual sex was the instrument of man’s participation in the sacrum, in this case borne and administered by the woman; it was a technique to make an experiential contact with the divinity and to receive her. The trauma of the coitus, together with the interruption of individual awareness that it caused, formed an especially favorable condition for that contact.
Link: http://www.sexmagick.com/aisha/aq_name.htm
I also found information regarding a ceremony to keep a young girl young forever....that could also be a theory to what they were trying to acomplish.
