Me too, though of course in our day, the world was much less connected and much less reliant on the technology. The worst we could have done after getting root access to the entire IT infrastructure at my school would have been look at what our classmates had been drawing in Paint or something. Today these systems host much more important and sensitive information and security breaches would be a much bigger deal.
And on that note, am I the only one less concerned by the behaviour of an impressively curious seven-year-old and more concerned by an official, professionally-managed system holding potentially sensitive data that is so insecure that even a seven-year-old could hack it?!