For any labour - first, second, third... I always suggest to keep an open mind. Go in and give a natural birth your best shot, but there's no need to feel like a failure for asking for pain relief if you need it.

I wanted a natural birth with my first and ended up having to be augmented with a drip and couldn't handle the pain. Gas made me sick (possibly because I had eaten a big meal that afternoon) and I went for an epidural and was very happy to enjoy my labour. Second labour I wanted an epidural but arrived into hospital at 8-9cms so I had to have a natural birth. Both labours I am very happy with the outcome - two healthy babies

Things can always happen differently than you expect them to, so an open mind might help you relax a little more. I let me body do what it can, and if I can't cope, I know I have a back-up plan if I need it.