It's never to early to start thinking about these things!
I didn't plan to have a water birth, I don't know why but I just didn't fancy the idea of one. Fast forward to me being in labour... I was only 1cm dilated when they checked me at the hospital but my contractions were hardcore and I was in absolute agony. After some begging (lol) they let me stay in for a while, at least until they needed the room for somebody else. I spent the next two hours in a LOT of pain (wasn't allowed pain relief as not in "established labour"), to the point where I was throwing up. It was at this point where the midwife suggested I take a bath in the birthing pool to help ease the pain. I remember thinking "yeah right, as if" but as soon as I got in that water.... OH MY GOD... Bliss!!! I could still feel the contractions but they were so much more manageable than before, I was even falling asleep inbetween contractions and hubby had to keep waking me up. It was an incredibly serene almost out of body experience for me once I got in that water.
After just under an hour of being in the pool I could feel myself pushing. At which point they had sent my husband out to get something to eat as they said it would be "hours yet", but that's another story lol! Well, when I finally managed to convince the midwives that LO was well and truly on her way out, my mum was frantically calling my husband to get him back, and Chloe was born about 5 minutes later! I didn't find delivery particularly painful. A lot of people talk about the "ring of fire" but I didn't feel any of that.
I did sustain a labial tear during the birth. Didn't feel it at all at the time but it was very painful in the weeks after and became quite badly infected.
I would ABSOLUTELY choose a water birth every time if I could. I am actually quite scared of NOT being able to have a water birth next time round, if for example there was no pool available at the time. For me the whole experience changed when I got in the water, everything seemed so much better.