AA only refers to the front cabin in 2-class aircraft as "First" for domestic US flights.

Even before this recent change, flights between the US and Canada/Caribbean/etc were marketed as business.

Since you are originating in Canada, it is called Business class for the flight to the US. If you connect to a domestic flight, the cabin will be called First.

Either way, it is now business class for tier points.

3-class transcontinental flights still have both business and first...but those are limited routes...JFK-LAX, JFK-SFO, and some MIA-LAX.