I am 31 weeks with my first and am super excited to do a water birth! There is a water birth center close to my home too with amazing midwives. I feel way more comfortable going there than to a hospital. My OB wasn't very helpful or made time for me and made us feel very rushed. Our midwives take the time to help us and make us feel at home. It is a great feeling knowing that we are not just a name on a chart with dollar signs.
Plus I hear that water birth is 70% less painful during the labor process since the water helps lift the belly and alleviate any pressure from gravity, you can move through the contractions instead of being stuck on your back, if the cord is wrapped around the baby's neck its easier to remove in the water, and the warm water helps to relax the muscles.
I used the hot tub at the hospital, but it was designed to continue heating the water and after a while I was simply roasted out. Also the midwife assigned to watch me kept her eyes glued to me the whole time looking speculative, (she was the one who commented on my age also), so I felt super creeped out by the time I got out.