This may sound harsh, but if the throws were checked and the C.G. was checked then it may simply be you didn't have enough time under your belt to trim a model that needed trimming on its maiden flight. best to have a trainer/instructor put a first flight on an untried model - especially a fast one. A sleek ducted fan model doesn't allow you to try stick corrections at low altitude and if you fed in the wrong control . . .

You have to keep ahead of it - not react to it.