Hi,
As a teacher, the pieces do initially look hard, but I think that if you are really keen, and enjoy the pieces you have choosen, learning them quickly won't be too much to handle. Have you considered at looking at the pieces outside of the selected pieces? Although I'm not teaching grade seven this coming academic year, the Skryabin prelude in G flat, in the B list, is not too bad, and neither is Sylvie Bodorova's Carousel. However, if you are one of those pupils who would rather stick to the book, well... from the A list, A1 or A3 don't seem to daunting. With A1 make sure you use consistent fingering, and with A3, plenty of good old hands separate pratice is in order. B list... B3 is all right, just need to bring out the melody and read your ledger lines carefully. And as for the C list, C1 or C2!
Hope this helps.