You did a great job! I really like how you were able to leave the pages in and you left the first page in. That first page is a really unique touch!
I make these book cases for my Nook Tablet, and I know how you feel. They ARE hard and very time consuming. Measuring the tablet and then adjusting it to the device once the pocket is sewn on (I sew pockets into the fabric lining) is a PIA! Half the time it doesn't even come out right and I have to add some trim to cover up the bad cutouts.
When I first got my Nook, I was hoping to make these book cases and sell them in my Etsy shop. Feh! No thanks
They're great to make every so often but not all the time.