We didn't tell anyone for as long as we could avoid telling just to avoid the issues. We finally had to come clean when some of dd's friends in the neighborhood knew b/c they were at school with her and she wasn't going to be at that school anymore the next year due to moving into middle school.
In our instance, dd is pretty obviously well out of the norm even in GT classes, so I can't say that anyone said anything (at least that I heard) about it being unwarranted. We do have other parents who have repeatedly mentioned how their kids are gifted too and who inquired about why dd was skipped or how we went about making that happen.
I, too, tried to be low-key and just replied with something like, "it is what the school recommended," which is true.
I understand what you mean about the "jealously" feelings even if that is not quite the right word. I think that it has something to do with the misperception that gifted kids come from parents who did something right. If your kid is less gifted than mine, then I did something better. One mom at dd#'s school referred to elementary parents as having a "pissing contest." It seems to be an extention of the parents competition that happens with babies -- whose walks first, etc.
I don't think that I've gotten as much in the way of competitiveness from parents of older kids, so perhaps it will abate a bit for you as well as your dc get older.
