I say if you want to go for natural, that's great! but definitely keep an open mind. With my first, I wanted a natural labour but once I was in labour I begged for pain relief, I would have done ANYTHING for an epidural at the time. They were telling me I wasn't in active labour and it'd be a long time until baby was born and I was in so much pain. Turns out my midwife was crap and baby was abour 40mins away from being born so I didnt have time for an epi anyway, I had gas and air and pethidine(which she shouldnt have given me if she'd have listened to me and realised I was actually close to pushing)
second birth I said I wont plan anything until its happening and id do whatever felt right. I had another quick labour with about 40mins of gas and air and breathed through most of it. Was a great labour!
This time again I'm going to go with the flow and do what my body tells me but after having two quick labours 3hrs first and 4hrs 2nd if that happens again i doubt ill have time for an epi but would never say never.