So, I have a friend a couple of years younger (less than 5) than me who uses the term "cooch" to refer to her vulva. To me, that term is vulgar and a bit offensive, and she says that she often gets that reaction from people not much older than herself. However, it's what she and her friends all used. There was something about "coochy pants" too, which I guess are low cut pants?? Apparently I missed all of that being in HS a few years ahead of her. I think that how offensive words are depends a great deal on what you grew up with as well as context and audience.
I'm 28 years old and graduated HS in 1998. I personally find pussy to be a bit offensive, but not nearly as much so as many of the women on this thread. I would certainly not chose to use that word myself. I find cunt to be highly offensive. Then again, I find most slang terms for vulva and/or vagina a bit off putting at least. I didn't hear the word "yoni" until I was in my 20's and had been married for several years. Maybe I'd have taken that one up in HS if I'd heard it then. I generally used clinical terms with my peers, (not that we discussed our vulvas often) but we were all geeks and used clinical terms for many things. My mother taught me the term vagina as well as penis and so on from a very early age. I was comfortable using all of that with her, though we didn't often discuss sex. My DH and I, who dated throughout HS, made up our own words over the years - generally things most people wouldn't think were sexual at all. I'm quite comfortable discussing sex, my vulva, his penis, and so on with him, both in clinical and not so clinical terms.
I too think it's awesome that your DD felt comfortable refering to her vulva in general context with you.