I was pretty open minded about labour as long as little one was ok, but I definitely was not prepared for what happened - our baby came at 36 weeks, waters broke at home and just after we arrived at the hospital I had a cord prolapse so I was under general anaesthetic and our little girl was delivered extremely quickly (we were so lucky we were at the hospital when it happened). It would have made all the difference if my husband had been allowed to stay, and the nurses on the ward hadn't made me feel like the worst mother (they said things like "I had cuddled her too much and spoilt her and that's why she was screaming so much"). But I was completely overwhelmed and had flashbacks / nightmares for a long time after. I have since had a debrief with a lovely midwife at the hospital, which helped massively, and she has taken on board my complaint about treatment afterwards. The midwife who was there when everything happened was also amazing, I'll always be so thankful to her for acting as quickly as she did.
I think it would have helped if I'd known about what could possibly happen / go wrong during labour... whether that's through antenatal classes, community midwives or just me reading up more about stuff. I think I thought I was doing the "positive" thing in not reading the scarier stories, but it might not have been such a massive shock had I known that could happen.