There’s actually a very interesting Chasam Sofer where he says that the whole twenty-years-old-chayav-in-dinei-shamayim thing isn’t really true. According to him, the only difference is that when in certain times in history there was a gezeira for people to be wiped out – such as the dor hamidbar – it only applied to those over the age of twenty, but this rule has no application to us.
In other news, today is the fourth anniversary of my twentieth birthday. I’m getting old.