Tax Home Establishment Date in Foreign Country

What would be the official date that I established my tax home? 

 

I moved to Canada for school around August 20, 2017. When filing 2018 taxes, I did the physical presence test using the dates 01/14/2018 to 01/13/2019. 

 

Is my tax home establishment date the day I moved (Aug 20), the start of the physical presence test (01/14/18), or the end of the test (01/13/19)?