If the Earth is a home to forming entities, and the Council of Worlds is regulating visits between entities who have graduated from such homes to travel about the Universe, then just how ancient are such entities sitting on the Council? The length of time is not a relevant guide here, as progression in spiritual matters is less a matter of years but a matter of growth. There are old souls in the Service-to-Self camps that have barely progressed past the point of most immature souls on Earth! They are firmly Service-to-Self, and thus progressed to 4th Density, and there they sit. There are relatively young souls who move rapidly through the densities, as by their nature they learn rapidly and do not hesitate to apply their knowledge. And in between are the vast majority, who linger at points, revisit areas they have passed through before to solidify lessons, and become blocked due to their natures now and then, moving beyond the blocks only when they realize that this is preventing any forward progress.
In human society, you have this equivalent, but this is overshadowed by the natural handicaps that the very young must struggle with. The tiny babe, helpless to feed or move or bath itself, is clearly unimpressive to humans, regardless of the wisdom inherent in the incarnating spirit. The toddler, struggling to communicate in single word phrases, is treated as a potential only. The youngster, eager to learn but often bungling in their attempts to create even the simplest contraption, are held in esteem only by loving parents and relatives. The teenager, who may be accomplished and speak great wisdom, is overlooked as they are assumed to be rebels and speaking only to assert themselves in their desire for independence and self importance. Thus the idea that a relative youngster could have wisdom beyond their elders is incomprehensible to humans. How often, from the mouths of babes, come great insight? How often do the mutterings of mature humans in their prime show that their thinking is cluttered with dependency longings, irrational resentments, self-promotion, and an inability to be creative or resourceful? Age means nothing!
A soul is unaware of its status, but tends to recognize other strong souls during an incarnation. The human form is a great mask, in the main, except to the educated. Old souls almost instantly recognize each other. This is not a body language issue, as the human can be unaware of the age of their soul, other than that they find they are focusing on issues differently than others around them. An old soul often finds they are strongly at issue to Service-to-Self agendas, or take action suddenly to situations where others about them are debating and unsure. An old soul often has a skill set that surprises the parents, expressing early in the life of the young human whose knowledge and skill are coming from a source other than the education being given by the parents. Thus, there are clues, but the old soul in a young body feels, most often, strange and apart until meeting others of his kind.