He won against the odds before and this time he didn't. I don't know really if there was any relevance in her being 15 or 16 as in modern society both ages would seem too young to get married.
Not really.
In Australia, 16 year old women could marry without legal restriction until 1991, when the Sex Discrimination Amendment Act raised the age to 18, to match the age requirement for men. Women aged 16 and 17 can still legally marry in Australia with the consent of the courts.
In the United Kingdom, 16 and 17 year olds can marry with the consent of their parent or legal guardian (Consent is not required in Scotland).
In France, 15, 16 and 17 year old girls can marry with the consent of one parent.
In Germany, 16 and 17 year olds can marry but require both court and parental consent.
In Andorra, 14 and 15 year olds require the consent of the courts to marry; 16 year olds and over can marry without legal restriction.
The US States of Missouri, Hawaii and Georgia all allow 15 year olds to marry with parental consent, and New Hampshire allows girls as young as 13 to marry with both parental and judicial consent.
It seems that there are plenty of modern societies where 15 or 16 is not considered too young to get married; and even a handful that allow marriage for people as young as 13 or 14.