Residency and legal residency are different. Your home has been in Canada, so my guess is that you established residency there at some point. When you begin to reside in a new place then you will be domiciled there, and will establish new resdency. As ll pointed out, you may need to meet some minimum period of residency for some purposes, but not for others.

You have nothing to lose by discussing your situation with a representative of the school you are planning to attend. They should be intimately familiar with the specific rules for residency for determining tuition at their institution. You could get lucky.