I think it definitely does depend on the child, but I've seen some definite drawbacks to graduating at a younger age. We had one graduate at 16 and one at 17 (the 17-year old then graduated college early at 20). Both felt that there were some practical drawbacks in terms of little things - work meetings at bars (maybe she was just unlucky, but this seems to happen a lot), leasing an apartment, even being able to pay into her work retirement system - that turned into a convoluted mess where she was required to participate, but also required to be 21. And yes, it seems like it would be simple to fix, but it's been a hassle!
OTOH, would I do anything differently? I don't know... certainly neither child was pressed to her intellectual capacity (one is PG, the other is untested, but certainly very gifted). They've always gotten on better with older kids, at least until college age, but honestly, there ARE some issues. I always hear parents on this board saying that their 8 year olds hang with 12-year olds, or their 14-year olds hang with 18-year olds, but I don't think that's ideal and I can't imagine it always works (it didn't work all the time for us). With my two younger kids, I've tried to keep them with their same-age peers, but worked much harder to find other outlets for their intelligence, creativity, etc... They're both in relatively demanding gifted programs, and they also have a lot of outside stuff going on. So, maybe school isn't always super challenging, but they find other ways to stretch themselves.
I'm not at ALL criticizing kids who skip (obviously, since mine did) but I think sometimes it should be acknowledged that neither option is ideal. Most of us don't have the option of having peers who are the same age, same intellectual capacity, etc... so we make do with the best solution, but it's rare that either holding back or advancing is ideal.
As your daughter advances, I'm sure it will become more obvious what is the right-even if not perfect-solution for her. Just keep in mind that the most frustrating part of schooling for gifted kids, IMHO, is usually grade school. With all of my kids, the older they got, the easier it was to find the appropriate education (maybe once the teachers got past the "it will all level out by third grade" nonsense :))
