Elective c section but go into labour before the date

Happens to lots of people. They'll get you in As soon as they can, could be minutes to a couple of hours depending on what else is happening and availability of theatres

Yep happened to me. In my case if I'd got to 39 weeks it would have been dangerous to have a baby naturally, so that's why they'd booked me an elective at 38 weeks. But I went into labour naturally at 36 weeks so they gave me the option of having a c section the next day (my waters had broken overnight and I was labouring fine at home) or to come in for induction the next day and try natural birth, which I chose. Unfortunately the induction didn't progress my labour so the day after I ended up with emergency c section, it was about 30 mins after we'd made the decision would have to go down that route.