I think you have to study in Canada for at least one year to file for permanent residency. So, if you wanna do masters in Canada, hopefully you get your PR card within two years (u can not apply until a year and it will take another year to process). If you can sustain in Canada for two years (I mean paying for college and living expenses), it might be a good idea otherwise, you can apply from the US (if you live in the US now) and if you qualify you get your PR in a year and then you can move to Canada. Nevertheless choice is yours...