I have thousands of Entities stored in the GAE datastore where a field "create" is saved as a date
Query q = new Query("Post")
Even if GAE has indexed date as string so '2014-12-11T14:31:43 -08:00' comes after '2014-12-04T14:31:43 -08:00' (just for example) which means natural sorting order should follow.
Have you indexed 'created' field? If not, GAE is gonna ignore the sort order you gave in query.