Ewww! Arya and Gendry

Nope, 18 (and the actress is older than that).
But it's not like people waited til they were 18 in medieval times. 18 was an old maid back then.

If Ned had stayed hand of the king and none of the events happened to the family he would have had his children married off. Only his firstborn son had "lands and title" coming to him directly. Ned would have worked out political matches for his other children. Arya would have been married off at around 14 to one of Neds bannermen's first son so she would have gotten "lands and title", Lady of . Ned's other sons would have been married off as best as he could since they offered nothing put political power (no lands or title).

It’s really surprising.

For seven seasons, we’ve seen a world where girls are married off to have children the moment they’ve menstruated for the first time. But when we see a young women having consensual sex, people go: "Ewww, gross!"