I hope you've talked to the ladies at Nicole's BA forum (
http://www.implantinfo.com/discussions/index.aspx). They're a fountain of answers and generally do seem to substantiate what your nurse said about most people wishing they'd gone larger.
One thing to consider, though, is that most women's clothing is designed with the average bust in mind. In clothes shopping I've found that for my size, a C cup is about as large as I could be and still wear pretty much anything off the rack. If I was a D cupper I would be much more limited in clothing choices and would have to dress carefully for visual balance. Of course, I'd also probably never walk into a room again without having people stare first at my chest. That wouldn't work for me. I like to blend.
I, personally, would never BA. Having scrutinized, I suppose, images of thousands of breasts of all sizes (don't judge!) I've seen far too many implanted ones that look just like that-- breasts with plastic bags in them. I find the tiniest natural breasts more visually appealing than the best implant work I've seen. High quality BA work seems to be rather rare, because the vast majority, even among professional models, have obvious flaws. These flaws include over separation, merging in middle, ball-like shape, unnaturally high bulging, and other things.
I'd be very happy if the oversize bosom finally went out of fashion in our culture and people realized how wonderful diversity can be.
~ Lyric ~