] Basically, all of the above. It's question that perplexed people living in JA's time, it seems. Mary Crawford spends a lot of time wondering whether Miss Price is out or not.

...Lady Catherine and Lizzy.

"Are any of your younger sisters out, Miss Bennet?"

"Yes, Ma'am, all."

"All!--What, all five out at once: Very odd!--And you only the second.--The younger ones out before the elder are married!..."

So, it appears to indicate that there was not only an age requirement, but also a sort of sending one daughter at a time into society to find a husband and clear the way for the next.