if something seems off to you don't simply shout, impossible, imposter, burn the witch! But think about the reason whý it might be so. In this case the reason is so obvious, I fail to understand how you could have missed it.
not everyone that can do something you cant or know something you don't is an imposter. "I don't believe your friend speaks French fluently, I bet he is just making words up!" "Well em... he is from France, so it is highly likely he knows how to speak French"