File::Find::Rule::Age allows you to return the newest file last.

#!/usr/bin/perl -sl

use strict;
use warnings;
use File::Find::Rule::Age;

my $dir = '/path/to dir';

my(@old_files) = find(  
    file => (),
    name => '*.pm',
    age => [ older => '1h' ], 
    in => $dir );
foreach my $old_file(@old_files) {
    print $old_file;
}
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