If they hatch anything you have a pair. You can crack an egg and check for fertility if waiting isn't an option. The egg yolk will have a visible white "bullseye" on it, if it has been fertilized. If not then you have 2 females.
Another question is, have you paid any attention to how many eggs have been added to the nest day by day? Geese lay one egg every other day so if the nest has had 1 egg added every day, you have two girls & The same if it's been 2 eggs every other day.