$ perl -Mstrict -Mwarnings -E '
    my $x = time; say $x;
    my $y = int($x - (25*365.24225*24*60*60)); say $y;
    my $z = (localtime($x-$y))[5]; say $z
'
1389999563
601076303
95

##</code><code>##

#!/usr/bin/env perl -l

use strict;
use warnings;

use Time::Piece;
use Time::Seconds;

my @YMDs = ([2004, 1, 17], [2004, 1, 18], [2004, 1, 19]);
my $now = localtime;
print 'Now: ', $now->strftime('%Y-%m-%d');

for (@YMDs) {
    my $dob = Time::Piece->strptime(join('-' => @$_), '%Y-%m-%d');
    print 'DOB: ', $dob->strftime('%Y-%m-%d');
    print 'Age: ', int(($now->epoch - $dob->epoch) / ONE_YEAR);
}

##</code><code>##

Now: 2014-01-18
DOB: 2004-01-17
Age: 10
DOB: 2004-01-18
Age: 10
DOB: 2004-01-19
Age: 9