How did gilly get in trouble the first day of school from great Hopkins?

It seems you're asking about a character named Gilly from a story called "Great Hopkins". However, there is no widely known story or book with that title or featuring a character named Gilly.

To help you find the information you're looking for, could you please clarify the following:

* Are you sure about the title "Great Hopkins"? Perhaps there's a slight variation in the name.

* Is Gilly a character in a book, movie, TV show, or another form of media?

* Can you provide any more details about the story? For example, what kind of school is it? What is Gilly like?

With more information, I can help you find the answer you're looking for.