] I'm not so surprised if women were obliged to marry when slightly older,but 25? And during an era when people usually died in their late 60s; Considering a woman's prime role in life was to be a wife and mother,this must have been very frustrating for gentry daughters.

But in a way they were lucky because thus the average birth rate for genteel women was "only" around five.

I have read a text book about American Souther rural society before the Civil war where child brides were quite the custom. This marriages resulted in woeful female undereducation and seriously overtaxed teenage bride responsible for a big household. Also the average bith rate was considerably higher, fifteen children and more were quite common in that place and era. Also when I read other accounts of very young brides elsewhere in that era, they usually had ten children and more (for example Tolstoy's wife was eighteen when she married, they had thirteen children, Dicken's young wife gave him eleven kids). I don't find that a desirable prospect at all.

I read in a biography that Jane Austen advised her niece not to marry too early(she was eighteen then) in order to delay the business with motherhood.

For the health and education of women, 25 was the perfect age for marriage.