before you know where you are

before you know where you are (or before you know it)

with baffling speed. informal
See also: before, know

before you know where you ˈare

before you have time to realize that something has happened: We were whisked off in a cab before we knew where we were.Before she knew where she was, her bag had been snatched and the thief was running away with it.
See also: before, know