If you just want to check which is later, reverse the order of the parts, i.e. yy.mm.dd. (Make sure you keep all fields fixed width, i.e. zero padded if necessary.)

Then simply compare them as strings! However, you are likely to run into the "Y2K" problem, since your years are only two digits.

#!/usr/bin/perl 
use strict;
use warnings;
use DateTime;
use DateTime::Format::Duration;


my @dt;

for (qw( 30.01.08 05.03.08 )) {

    local @_ = split /\./;

    push @dt,
      DateTime->new(
        year      => $_[2] + 2000,
        month     => $_[1],
        day       => $_[0],
        time_zone => "Europe/Paris"
      );  
}

my $dur = $dt[1]->subtract_datetime( $dt[0] );
$dur->is_negative and 
    warn $dt[1]->dmy . 'is older than ' . $dt[0]->dmy . "\n";

# Choose the pattern to feet your needs
my $dtfd = 
DateTime::Format::Duration->new( pattern => '%V weeks, %e days' );
my $formated_dtd = $dtfd->format_duration($dur);

print <<QUOTE;
Difference in weeks and days,
between @{[$dt[1]->dmy]} and @{[$dt[0]->dmy]}: $formated_dtd.
QUOTE
[download]

# Difference in days between two dates:
$diff = date('2001-08-27') - date('1977-10-05');
[download]