Characters are shown using a telescope, something not invented until at least the late 16th Century.
While writing in her diary, Birdy marks it October 16. The following day it says October 16.
Birdy's diary entry on January 6th says that "1291 is upon us." From 1155 to 1752, the new year in England began on March 25th.
While heart warming, the cancellation of Birdy's betrothal to Shaggy Beard does nothing to resolve the family's dire financial straits, the very thing which caused them to seek a husband for Birdy in the first place. Indeed, their financial situation has worsened since now they have to support Aelis as well.