I'd like to create a file with an invalid created/modified/accessed timestamp. To be invalid it should be a date and time before 12:00 midnight January 1, 1601 C.E. UTC
Look for a tool called Timestomp
The software's goal is to allow for the deletion or modification of time stamp-related information on files.
This is not possible.
File time is used in Windows API through the FILETIME Structure, described as:
Contains a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601 (UTC).
As negative values are not supported, the above date is the starting limit.
Conclusion: Your code which tests for earlier dates will never be challenged.