She can't even remember details of recent occurrences, like what took place during her interview with The Washington Post journalist. How can she possibly be trusted to know what happened 36 years ago?
Sounds to me like Ford spoke of two separate incidents to her therapist. One at 15 (Kavanaugh) and another incident while in her late teens.
From WaPo...Notes from an individual therapy session the following year, when she was being treated for what she says have been long-term effects of the incident, show Ford described a rape attempt in her late teens.
The prosecutor will use this.