I know she has now accepted responsibility, but I think it was forced out of her.
From the ouset, she appeared not to be sorry in any shape or form. We all understand it was an accident, she didn't deliberately drive into the poor lad, it was an error of judgment. So, if she had any kind of conscience she would have stayed and answered for her actions in a honest, timely manner, which would have helped ease some of the family's suffering.
Instead, after initially talking to the police, saying she wasn't going anywhere the next day she is back in good ol USA, spouting diplomatic immunity bullshit to avoid taking any responsibility for the accident. Kudos to Harry's family for keeping up their attempts to get justice