There's actually a bit of a misconception about ancient lifespans. The lifespan average takes into account all the population, which includes infant mortality, which was quite high for much of history. I think the statistic I saw for ancient Greece was something like 1 in 5 infants died. So for every infant that gets counted, it brings down the average. Once someone made it through childhood and into their teen years, they'd live to about 60ish, depending on the specific area and time.Several hundred years ago or so, the life span averaged about 35 years.
That would divide the years up better. Women were usually married and bearing children by age 15. Being unmarried much longer after that age would make you a spinster.
But you're certainly right that women married much younger and started having children much younger. In a lot of places and in a lot of times giving birth was sort of the main role of a woman, some societies saw that as the only real worth of a woman - and it was dangerous. A lot of infants didn't survive, and a lot of women didn't survive. I think it was Medea who said something like she'd rather stand in a battle line three times than give birth once, because of how dangerous it was.
All that said, again, maiden-mother-crone is a modern construct, less than a hundred years old, so it wasn't something developed in an older culture where all this was the case. Of course, even at the time of its creation women were generally still expected to get married and have kids (it's still a real pressure on a lot of women today), and there were a lot of modern traditions created which did focus quite a bit on the literal fertility and childbirth bit.
