Hello,
Over 2 means you're stitching over 2 holes instead of 1. This website has a great explanation and diagram of stitching over 2 for Aida or linen. Just copy and paste this link into your browser:
http://www.better-cross-stitch-patterns.com/over-two-threads.html
The size that is posted is for using a 32ct. fabric over 2 but you stitched this on a 16ct Aida fabric over 1, then your size doesn't change because 16ct. over 1 is the same as 32ct. over 2. So, if you changed it to a 14ct. or an 11ct. fabric which will have bigger holes, the size will change but not by much. There isn't a lot of detail to this design so changing the fabric count won't really matter. When designs have lots of detail in them, you usually lose those details when you switch to a lower fabric count because the holes are bigger. Hope that makes sense? But definitely check out the link I gave you on the "over 2" explanation.
~Kristi @ ECS