Have you checked your local code? You might not have a choice for the size of shed you're planning if you're in a cold climate.
It's not cold. Though I wouldn't have thought that would have hit any kind of limit. It's also an area where codes are generally not so severe. Though I should definitely run a quick check. The main reason for going with the size of the neighbor's shed was it looked like a good size and is proportionate to the land area.