Why have youngs shifted so anti-Democrat all of a sudden? 
As others have said the subsample is incredibly small and thus has a very large MOE which gives us these very strange results which are hard to corroborate/disprove given that we aren't getting multiple swing-state polls every couple of weeks.
I certainly don't think we should take this as any indication that Christie has any unique appeal to young voters - though he certainly might given his less vitriolic approach to social issues - as most of the young voters who know him best (those surveyed in NJ for the Governor's race) support him at considerably lower rates than their elders.
