Most Helpful Guy
I'd ask at the end of the first date I think. If she didn't like the first date I'm pretty convinced I'd have realised that during the date, in which case obviously I would not ask about the 2nd date.
Most Helpful Girl
Usually they suggest/schedule a second date by the end of the first date if it goes well 😊 but if not, they maybe wait a few days, but not too long as it would probably give her the wrong message.