I remember there are some clues in the book, like the year of birth of Hiro's father and his age when Hiro was born. I don't remember if Hiro's exact age is specified.
So, has someone calculated the year when Snow Crash takes place?
I found the passage where some clues are given: Google Book, Snow Crash, page 57
Hiro's father had joined the army in 1944, at the age of sixteen
1944 - 16 = 1928
Hiro was born when his father was in his late middle age.
1928 + 55-59 = 1983-1987
So the only missing piece is Hiro's age.