I don't want to throw FUD around, but I would say a long while. Even if there's 0days they'll probably be withheld since the rest of the iOS 13 spectrum is covered for now and its a minor update.
If you just bought your phone, might be worth doing a retail exchange and rolling the dice. IF you have AC+, depending on how much you value jailbreak, might be worth burning an incident to hope for older stock.
Just a thought