Just go with it. Seriously, worrying is not going to get you anywhere but down. I got myself in a right old tiz with my first, and I had a very short and lucky labour. No, that's not always the case, but worrying about it for months and picturing the worst case scenario will only make you more tense and scared. The big bit of advice I can give you before labour is when the contractions start, KEEP BUSY. Mine started at 5am the morning before I gave birth, but luckily I was going to see family that day. We went shopping, for lunch, watched films etc, the whole time me having twinges, and by the time I left them in the evening I had been so distracted that I didn't end up going into hospital until midnight- she was born at 2:15am! The midwives told me there's nothing worse for a woman in labour than getting into hospital too early, and having to turn around and go back home again.