My eldest who skipped 5th to enter 6th this year defined success for herself as performing as well in 6th as she had in 4th albeit with somewhat more effort. Admittedly it would have been hard for her not to exert more effort in that she was basically doing nothing in 4th to earn the grades she was getting. In that regard, she was successful. To me, if your dd is achieving the same (doing as well as she was in the grade she was in last year), the acceleration has not been a failure. Hopefully the school will not view it that way.