Infield Fly if you don't call it immediately

[bellnier]

(I tried posting this earlier but it didn't show...sorry if it appears twice then).

Batter has 1 ball, one strike; 1 out, runners on 1st and 2nd. Batter hits popup whose trajectory from vantage point of PU indicates ball will land 2-3 feet inside line and well short of 3B bag. PU yells "IFF". Fielder waits under ball, which she then cleanly misses. Ball drops at her feet, rolls across the line and settles foul. Is it a foul ball and the batter gets to continue batting? Or is it an infield fly since all the conditions were met (especially since the fielder had a chance to catch the ball with normal effort)? Is the batter out? Thanks in advance from an obvious 'non-ump'.