Dreaming about a car, especially in an unusual setting like inside a house, can symbolize various aspects of your life. Cars often represent your direction in life, control, and the journey you are on.

In this dream, your stepsister driving her car into your house may suggest a feeling of intrusion or changes in your personal space or family dynamics. It could reflect a desire for more connection or interaction with your stepsister or signify a blending of family boundaries.

The act of slowly driving out of the house might indicate a gradual transition or the need to establish boundaries again. It could suggest that while there may be influences from your family or stepfamily, you are still in control of your personal space and life choices.

Consider your current feelings towards your stepsister and any ongoing family dynamics to gain further insight into this dream. If you feel positive about your relationship, it may symbolize harmony; if there are tensions, it might reflect unresolved issues.