Maybe she just needed the money. Paying later always has the risk that it will never going to happen. And she helped you, did she get anything in return?
Good. I don't doubt your good intensions. Just thinking that even though you would have paid her in the next convenient occasion, she would still have suffered a (semi-) financial loss because of the increased risk she was put under, of not getting her monmey back if you were run over by bus. Cheers :-)