It would appear that the previous expert has opted out of this question. So I will pick it up from here.
I believe you are worried about an accident that occurred in your building back in 1977. Illinois has criminal and civil statutes of limitation. Statutes of limitations are laws that control how old a case can get before it's too old for you to be sued or prosecuted.
In Illinois, assuming that you ever had a duty of care towards this girl, the civil statute of limitations would have run out two years after she turned 18. So the fact that neither you nor your parents were ever sued for this then means it's much too late for that to happen almost 40 years later.
Similarly, if you'd committed any criminal act, the state would have had to proceed against you for 18 months if this matter was a misdemeanor or three years if it was a felony. Either way, it's much too late for anything to happen now.
So you have nothing you need to be worried about and you don't have to carry this on your conscience. You can't get sued or arrested for this matter. While it's not a good idea to talk about this incident, like your first expert said, you face no criminal or civil liability for this action. If you feel morally accountable somehow, professional counseling may be useful to help you overcome that, but you have nothing to fear from the law.
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