I’d like to try living, in the time I was granted

I was fifteen. We're kind of varied, from eleven to eighteen mostly... oh, but Yachiyo contracted when she was twelve and she survived all the way to nineteen! She's a veteran!

[ She's so proud of this. ]

You've got a point, though. From what I can tell, Kyubey also makes the offer when you're at your lowest or most desperate.