It’s unclear if Violet has told anyone else (like Mrs. Kresney, her counselor) exactly what happened during the accident. But it’s nevertheless telling that she chooses to tell Finch now, as this shows how much she trusts him. Especially considered alongside the fact that Finch got Violet into a car again, this suggests that Violet and Finch’s relationship is helping Violet to heal. Finch is providing her a space where she feels safe, and as though she can talk about these difficult experiences without people accusing her of being unwilling to move on.