Quite a few of our athletes have similar problems when they start – usually due to tight wrists / elbows / large upper arm
we do a lot of stretching in these areas to help and we also use auxillary training with straps over the bar and front squats in the clean position- instead of holding the bar in the clean position – you hold the straps in the same – and let the weight gradually increase your flexibility – the straps will allow you an inch or two of extra freedom to start – you can work on perfecting the rest of your position and have a gradual stretch into a good clean
I would estimate that 90% of athletes can get this clean position mastered with time