The nature of the relationship between Sandor and Sansa has been a hot topic on Revanshe's board. Sansa's youth has been one focus of the discussion. What is the general Westerosi view as to romantic or sexual relationships involving a girl of Sansa's age and level of physical maturity?
A boy is Westeros is considered to be a "man grown" at sixteen years. The same is true for girls. Sixteen is the age of legal majority, as twenty-one is for us.
However, for girls, the first flowering is also very significant... and in older traditions, a girl who has flowered is a woman, fit for both wedding and bedding.
A girl who has flowered, but not yet attained her sixteenth name day, is in a somewhat ambigious position: part child, part woman. A "maid," in other words. Fertile but innocent, beloved of the singers.
In the "general Westerosi view," well, girls may well be wed before their first flowerings, for political reasons, but it would considered perverse to bed them. And such early weddings, even without sex, remain rare. Generally weddings are postponed until the bride has passed from girlhood to maidenhood.
Maidens may be wedded and bedded... however, even there, many husbands will wait until the bride is fifteen or sixteen before sleeping with them. Very young mothers tend to have significantly higher rates of death in childbirth, which the maesters will have noted.
As in the real Middle Ages, highborn girls tend to flower significantly earlier than those of lower birth. Probably a matter of nutrition. As a result, they also tend to marry earlier, and to bear children earlier.
There are plenty of exceptions.