'I think it was 15?' Kourtney asked her, as the two played a game called Know Thy SisterKhloe, 31, confirmed the age, revealing she had written it on her whiteboard, but not giving any further information.
The two then revealed that Kourtney's first kiss didn't happen until she was a little older.
Asked by Khloe if she was in 5th grade - at around ten-years-old - Kourtney replied with mock horror: 'What? Who do you think I am?'
When Khloe asked her '8th' it then emerged she wasn't exactly sure of her age.
'I dunno,' said Kourtney. 'I remember it being a late first kiss. But I made up for it by doing more than just kissing.'