"Do you have a DNA test or are you taking someone's word for it that she is your mother ?"
Just taking someone's word for it right now. A test could be done if I really wanted to be sure. She certainly functions well as my mother, so I doubt the need will arise.
Except for their being more witnesses to Jesus's life than there are to your birth, it is no less rational for someone to accept the testimony of the witnesses to Jesus than it is to accept the testimony of your mother. In fact, you as a skeptic require less evidence of your mother's claim.
Testimony from multiple witnesses is far stronger evidence than a vision or an event that only one person sees. Like what you described you wanted for evidence, it could be the result of mental illness. But when many people witness the same thing, the likelihood that it happened is greater.