I was quite happy in labour with my first DC, but then chose to ask for an epidural when it was clear he was OP, stuck, and we needed a ventouse delivery. Even then the mws suggested I would have been OK with G&A - not sure why I didn't try that, but I didn't.
Mental prep: I told myself that whatever birth was like, it wouldn't go on for longer than 24 hours (I wasn't right there, but never mind!), and also that it would be like climbing a steep mountain - it may be very uncomfortable and hard work half way up, but generally you keep gping through the worst bit, to get to the top. I decided that the most important thing was not whether or not i ended up in hospital, or having pain relief etc, but that whatever did choose I would would do the choosing, based on advice.
What we did: Had a pool, and a TENS machince. i put the TENS on at the first twinge and used it thorughout until I got in the pool. Kept likfe normal - walked about, sat in garden, ate, cooked, talked on phone, for as long as apossible. kept upright - knelt on sofa leaning over the back during contractions. I breathed: and went 'uuuurgh' a lot, just to make breathing an activity in iteself, really, which was distracting!
With these techniques, I was honestly quite happy - yes, it was hard work, and uncomfortable, but not actually painful - but when it was pbvious to me that we really did need to tansfer to hospital, I panicked when i had to lie on my back for monitoring / ventouse, and it was suddenly painful (they had tried a drip to see if a bit of help would push DS out), and that's when I decided to ask for an epidural. And felt calm in that decision.
I hope everything goes well and easily