/ic/ - Artwork/Critique

Workbook says this should take about 45 minutes to an hour to copy, and it's taken me more than twice that long already and it's not even finished.

Am I doing something wrong if it's taking me so much longer than it should? I'm trying to improve my sighting, so I'm measuring and correcting stuff a lot, which I'm sure is slowing me down. Not sure if time is something I should even be concerned about; the workbook suggesting a time frame just makes me wonder.