When Saint Rita was born, how old was her mother?

Question

A question about hagiography. It is said that Saint Rita's mother Amata Ferri was old when her daughter was born, and she had been sterile for a very long time. But how old was she, if anyone knows her biography (even an approximation if you have).

Answer 1

Ch. 2, "The Birthplace and Parents of St. Rita," of Sicardo & Murphy's 1916 biography of her says Antonio Lotti and Amata Ferri were married in 1309. Ch. 3, "St. Rita's Birth," says "The biographers of St. Rita give the day, date and year of her birth as Saturday, May 22, in the year of Our Lord 1381, during the pontificate of Pope Urban VI."

So, assuming she married at an age of 12* in circa 1297, this means Amata was at least 84 years old** when she had St. Rita.
^{(If she married in her 20s in circa 1289, she would've been at least 92 when she had St. Rita!)
*the youngest age, according to canon law, that a female could marry back then, assuming she reached puberty by then; in fact St. Rita herself became a wife at 12 years of age according to this
**cf. Abraham's wife Sarah, who was 90 years old when she had her first child (Gen. 17:17)}

Ibid. says:

Words cannot describe the indescribable joy of Antonio and Amata as, with loving eyes, they gazed on their little daughter whom they considered a precious gift of God, the fruit of their desires, and the reward of their long years of hope and confidence in God. The unexpected news that Amata Ferri had become a mother in her old age was the cause of much surprise, talk, and gossip among the inhabitants of Rocca Porrena. All considered the event as truly miraculous. Every man, woman, and grownup child of the little hamlet went to offer congratulations to the happy and overjoyed parents, and all who gazed on the smiling face of the newborn babe were charmed by the radiance of the little one’s wonderful beauty.