I am playing Grade 4 exam pieces?

I am currently using the "Keys to Stylistic Mastery Book 2", and as I was learning and playing one of the pieces for my teacher, she found it almost exactly the same to one of the Grade 4 exams pieces.


I was playing the Baroque piece: "Prelude" by George Frideric Handel

which is almost exactly the same as:

The Grade 4 exam piece: George Frideric Handel: Allegro in F, HWV 488


But mine is in G major, while I think the Grade 4 exam piece is the original piece, which is in F major. And mine has more performance directions, I think they were all editorial. But of course, my playing is not yet of performance standard, but good enough to pass the assignment by my teacher's standard. I was like, no wonder I find the pieces in the book so challenging. I used to be able to clear each assignment every week when I was using Book 1. But now, I am stuck at each piece for weeks! Ok, hope as time passes, I can clear the assignment in this book with a breeze =)