I'm definetly bigger than before, but its ok!
Since giving birth to my first (which was long and prolonged) my vagina was stretched and did not seem to be going back to it's normal pre pregnancy dimensions, which was probably a fault of my husband who was fascinated by my new vagina and he couldn't leave it alone and after a period of discomfort I couldn't resist his attention either and really enjoyed it. My vagina has remained reasonably constant (as in still stretched) over the years and after the next two pregnancys, but it doesn't seem to have gotten any bigger, but I seem to be able to accommodate a lot more.
I never got used to it filling up with water, but have grown to live with it, still gives me a bit of a surprise, no matter how I prepare for it. If I persist, I seem to adapt to the temperature after a few minutes.