I am the mother of the 9 year old girl who is never invited. My DD is developmentally delayed, but not to a point where she is unaware (as some people would like to believe). Honestly, while it hurts her, I use it as a life lesson. Nobody told us life is fair ! One way or another she will have to get used to it,so we might as well start now.... It KILLS me as a mother to see my daugter suffer one more time over something that is just not her fault-she really has a great heart but it is so uncool to be "slow". So, I wouldn't lose any sleep over this-just remind your daughter to be kind and gentle to the kids who weren't invited and sometime when your child is on the recieving end-use it as a life lesson for them.It's all part of growing up.