Neophyte can be seen as the symbolic or magical birth of the initiate, from the darkness of the Womb of Matter into the Light of the Spiritual World. Even the thrice-bound cord around the candidate's waist can be seen as the symbolic umbilical cord, which is removed as the initiate enters the Light of Day, and is, as a newborn, given a new name.
The Elemental Grades are, therefore, the magical childhood of the initiate, and involves much learning. Just as a child must learn their ABCs, so too must the magical child, who does so in a figurative way (the ABCs of astrology and Qabalah, for example) and a literal way (the actual Hebrew alphabet). The magical child must learn the material that develops their mind, but they must also learn some key magical "life lessons", akin to what a child in normal life must learn. This include learning that the world does not revolve around the magical child, and thus a strong rebuking, as it were, of the ego, which, if left to its own devices, would run rampant and suppress the true Self which is developing and unfolding during this period. Moderation and balance is another key lesson, as is not biting off more than one can chew or sticking one's hand in a fire. These are, in one form or another, exemplified in the structure and safeguards of the Elemental Grades. And, just as childhood is a necessary prerequisite to adulthood, these grades are absolutely essential as part of the system of the Golden Dawn. Adepthood can come without them, that is true, but eventually such an Adept will need to go back and face their elemental imbalances, whether they like it or not. Indeed, often one trip through the cycle of elements is not enough, and this is partially why a similar sub-structure can be found in the sub-grades of Adeptus Minor, where the elements (among other things) are experienced on another, higher level.
This leads us then to magical puberty, which could be seen to begin roughly in Portal. The magical child finds their astral body changing, because there is now an influx of Light, of Spirit. This can be a chaotic time, as the final dross is purged from the system and the transformative process is undergone. Yesod can be seen as the athanor in which the energies of Malkuth and Tiphareth are mixed together, and this is where the process of extracting the spiritual gold of Tiphareth, the prima materia (which is technically of Kether and above, but is experienced in a kind of "tamer" form in Tiphareth), from the dross of Malkuth is experienced.
This leads on naturally to Adeptus Minor, where ideally the magical maturity is developed, but often this is not so. What I mean by "magical maturity" is a non-dependence on others for spiritual growth. No longer is the initiate being spoon-fed lessons, as is the case in the scholastic system of the Outer Order (which is not to denigrate what is ultimately a necessary and honourable role), but they are now free to pursue their magical path, answering primarily now to their Higher Self, an internal, not external agency, with no one any longer holding them by the hand. Indeed, much of the hidden elements of the prior initiations has been specifically designed for this awakening, to stimulate the contact and communion with the Higher Self. Of course, this does not mean that the initiate can or should ignore the Chiefs of their Order, for example, or think they can change rituals and so forth willy-nilly; nor does it mean that they should shun papers and teachings given by other Adepts, many of whom have developed their magical maturity for quite some time. To think such only shows that magical maturity has not been attained, and in its place the Vice of Tiphareth, of false pride, has grown supreme. The mature adult of the normal world is independent, but is also not foolish enough to think that he or she should refuse help or guidance when offered or required. Likewise for the magically mature.
One of the key elements of magical maturity is the ability to think for oneself. While this may seem like an obvious matter, and one that all of us would like to think we have, it is, in this context, rarer than we think. It involves the ability to get one's own insights from material, rather than simply reproducing and regurgitating the insights of another (this is not an excuse to not properly cite or quote references, however). This does, of course, mean that a deep and true understanding of the material is required, but without this how can someone truly call themselves an Adept?
This magical maturity should also reflect a general maturity, such as a temperate nature, able to show kindness and compassion, but also sternness and severity when required. Both spheres of Geburah and Chesed feed into Tiphareth, and thus the qualities of both should be fortified and utilised by the mature magician. General childish behaviour is an obvious indicator of lack of maturity in the normal world, and is likewise a reflection of this in the magical world.
May we all, therefore, embark on this path, no matter our personal grades or spiritual standing, with a level of maturity in mind (even if there are many years to go before our own Adepthood). In the end we are all Children of the Light, fellow Brothers and Sisters, answering to our older Brothers and Sisters: our Higher Selves. May we embrace our own magical childhood, puberty, adulthood, and maturity, and that of others, and may we do so with the blessings of Adonai El Chai Melekh ha-Shamayim va-Aretz.