The Amarr were a global society for 700 years, and an interstellar society for 600 years before the Moral Reforms. Going by the length of Zaragram's rule, it's clear that life extension technology already existed in this time, and it's reasonable to assume that treatments such as prolonging fertility would also have been available - even if it'd just be saving eggs for later implantation.
I definitely agree that the Moral Reforms were a societal pivot point though. The main change was of course that the noble class rose above the clerical class, and that would have opened up for new and extravagant customs that may have been taboo in the previous system.
One thing I've been pondering for some time is the Amarrian "cult of age". Where the Gallente society likely worships youth for the same reasons we do today, and the Caldari might admire middle-age as a balance of experience and strength, the Amarr consider age to be a person's prime. Living to be old is a sign of being blessed, of having good breeding, wealth to access technology (like having wealth to eat yourself fat in medieval times), of having had time to take power, to establish many contacts, and of having more wisdom to know God.
In Amarr society, being (and looking) old is an ideal, just like looking young is an ideal in our society.
Having a child when you are very old might be considered an admirable achievement, because someone who has lived to be old deserves to further his or her bloodline.