To name a soul “old” means to measure it in time with the empirical instruments we use to measure such things as age, seasons, generations. Things which by default oppose the notion of the soul itself, which is eternity because timeless. Can we measure eternity by years, seasons, generations?
I prefer to think of the circular evolution of a soul, the spiral evolution bringing to eternal perfection. Through the various incarnations, a soul has the chance to evolve and learn her lesson: because if actually a soul was right from the start perfected, then she would be some kind of god, having already reached the zenith: nothing left to be learned.
The soul seems to me is eternal in a permanent state of evolvement towards perfection. How many times is she reincarnated seems to be pretty irrelevant: maybe hundred, maybe uncountable times: it is not interesting. What seems to me more relevant, is how good the previous lesson(s) is/are learned: because I believe that all souls will learn all that is to be learned, and in which order they will is also irrelevant.
I am of the opinion that a soul is a little bit closer to perfection when she realizes pretty fast what she is here to do, why is she this time reincarnated. If 40, 50, 80 human years have passed and still the soul has no clue why she is here, what is the reason behind all this suffering and/or all this happiness, then I think she has still lessons to learn, a way to go. It doesn’t matter if in this life the soul gets more happiness or more suffering: living in happiness is a lesson, like living in suffering is another kind of lesson. Because the perfected soul needs to know all lessons: the hard and the nice too... We all learn to hate, and we all learn how to love: and we need both, because everything makes part of the supreme knowledge.
I also hold the opinion that the NN indicates the lesson to be learned in this lifetime… And a lesson can be learned targeting into something, or avoiding something… As for the rest? The planets seem to me like the clothes given to this soul so that she is not naked, like the external shield... Or like the terms of an equation. They define the circumstances under which the lesson is to be learned. And again we learn both by what we are/have, and by what we are missing: I learn from all the planets I get in my chart, and at the same moment I learn by what is nto there for me (for example: I do not have one planet in water!! And the absolute lack of water makes part of my "education" process).
I find also that Astrology can help define these circumstances and thus help the soul gain time in its quest. Let's suppose that in this lifetime a soul must learn creativity through innovation (NN in Aquarius in the 5th)... She gets a little help: Jupiter in the 5th... Only that it is a Capricorn Jupiter, because the cusp of the 5th is actually in Capricorn... Saturn is squaring Jupiter from the 10th giving not only discipline, but also austerity: drying Jupiter up... But on the other hand, Saturn is trining the NN in Aquarius: discipline again, and a little assistance from people in authority (which never hurts...). The Sun in Taurus from the 9th is trining Jupiter, making the person of course a little lazy... But he will get opportunities: to travel, to higher education... However, the risk of losing his way is high: because the strong Sun is actually squaring the NN: so even the easy parts can prove to be misleading at the end...etc etc. Is there a perfect chart? No. All charts have their strong points, and their weak points. The opportunities, the difficulties, the hardships, the traps, the strengths, the weaknesses, the harmonies and the conflicts. Because the chart is the set-up for the lesson to be learned.
Think of life as a quest. Only that instead of searching for the Holy Grail, we search at the end for our own soul to meet. Not old, not young; not mature, neither infant: all these terms, either positive or negative, belong to our (human) system of measurement which has little to do with eternity, because is in effect both limited and limitating. Life then is a process. A flow.