Any female in a dream represents an idea coming from the emotional aspect of the self. The image of a female can simply be regarded as representing a feeling you have. When the female is old or just older than oneself, she would represent a feeling that has become a belief.

An old lady is definitely not an image of the unconscious.

What your scene can be showing is that a belief you have is not, or is no longer, speaking to you. This would imply the belief does not strike a resonating chord within you; it does not addresses your concerns.