Reading the title, I thought the only acceptable way they would be girlfriends for only 3 seconds was if they were to get married immediately afterward.
Lol who decides to marry the first person they kiss xD? It was cute nonetheless x3 Well played!
Also I feel like she is up to something with 3 seconds thing.
Given that she was counting down aloud in Japanese, 1 was the worst number to come in for the kiss. Her teeth were in the way of putting tongue in (Ichi)!