As if and as though

A few weeks ago one of my friends looked at my daughter and said "She looks as if she is not your daughter" is it correct to use present tense in a situation like that? The thing is that she knew that she was mine. Does the fact that she knew she was my daughter make this situation unreal? would it be better if she had said "she looks as if she were not your daughter"? thank you so munch in advance.