You are playing detective here. Why call her statements into question when you know very little about what really happened. Because of the magnitude of this reported crime, I would give her the benefit of the doubt until the evidence suggest otherwise. It is traumatic enough for her without other people "guessing" on what happened. The point is that important evidence was lost by the authorities not investigating this reported crime properly. She didn't have her day in court as she should have.
It's difficult to say for a single case, and difficult to gather accurate statistics for this sort of thing, but best estimates are that only around 10% of sexual attack reports are false (and only 2.5% of reports by children). Therefore, I'd be inclined to believe the story until there's some reason not to.