In short, I am a Mother, because I'm in the prime of my life. I can turn to those around me for support, but I habitually look after myself.
This zenith is no bright spark, which flashes up in one glorious moment and is then extinguished. It's probably the longest stage of our lives. No longer children, not yet old. It's the most useful that we can be in sheer practicality and strength.
The Mother is all about maturity. If I was a fruit, I'd be ripe and ready for the plucking. It's an analogy applied to many a Maiden, when she passes puberty and starts looking around herself with certain eyes.
But it continues to apply right up to the time when I'm past my prime. I won't say 'best', because who is to judge these things. This is the Three-in-One, there is no 'best' amongst those triple stages. Just difference in emphasis.
Because I have attained my maturity, I'm also fertile. In the obvious sense, and in many more ways that are less apparent. Have you read any of my history articles? When I was a Maiden, I imbibed the seeds of knowledge. Now I've passed my exams, now that I'm a Mother, I can pass that information on.
That's fertility. The seeds you scatter do not have to be living, breathing entities. The babies that you birth do not have to come from your womb.
Of course, real children are definitely part of the Mother's remit too. I haven't lingered on actual birth and raising little ones, because I'm assuming that's taken as read.