Sorry, i did not mean to delete my post where i asserted that a shot is 2.5 ounces. I was incorrect with the terminology and going with a colloquial. I was conflating drink and shot. My bad.
It actually depends on the alcohol by volume, yes. Most drinks i made were 2-2.5 ounces of hard liquor (dpending if it was straight alcohol or alcohol + liquer/cordial/brandy). The jigger we used to measure shots were standard bar jigger and double side 1-2 ounces.
The crucial information you are missing is how rapidly she drank the three. Three long islands in 3 hours would make you drunk, absolutely, too drunk to drive, but not de facto blotto. Most adults i’ve watched drink don’t go from zero to black out in three drinks unless there are other factors at play such as drinking very fast, not eating or being tiny. Your assertion she was automatically black out drunk after 3 drinks is based on a lot of information we do not have.
But i have to say, as someone who has been drugged/assaulted, i’m leaning toward drugged or being otherwise incapable of consent.