Etymonline gives approximate dates for those phrases:
Gambling was something both sexes took part in, although I suppose ladies limited themselves to cards rather than dice. I think there's a lot of gambling related phrases that have come into use, and (in my personal opinion) they wouldn't have necessarily been unsuitable for the ears of well-bred ladies.
Quote
Phrase at sixes and sevens originally was "hazarding all one's chances," first in Chaucer, perhaps from dicing (the original form was on six and seven); it could be a corruption of on cinque and sice, using the French names (which were common in Middle English) for the highest numbers on the dice. Meaning "at odds, in disagreement or confusion" is from 1785, perhaps via a notion of "left unsettled."
Quote
At sea in the figurative sense of "perplexed" is attested from 1768, from literal sense of "out of sight of land" (c.1300).
Gambling was something both sexes took part in, although I suppose ladies limited themselves to cards rather than dice. I think there's a lot of gambling related phrases that have come into use, and (in my personal opinion) they wouldn't have necessarily been unsuitable for the ears of well-bred ladies.