There are multiple ways to do so, here are three:

$ cat u.pl
use strict;
use warnings;
use Data::Dumper;

my @AoA = (
    [ "fred", "barney" ],
    [ "george", "jane", "elroy" ],
    [ "homer", "marge", "bart" ],
);

# Add to beginning of array
unshift @AoA, [ "pebbles", "bamm bamm", "dino" ];

# Splice into beginning of array
splice @AoA, 0, 0, [ "Fred", "Velma", "Shaggy", "Scooby" ];

# Rebuild with new entry at beginning
@AoA = ( [ "Bugs", "Daffy" ], @AoA );

print Dumper(\@AoA);

$ perl u.pl
$VAR1 = [
          [
            'Bugs',
            'Daffy'
          ],
          [
            'Fred',
            'Velma',
            'Shaggy',
            'Scooby'
          ],
          [
            'pebbles',
            'bamm bamm',
            'dino'
          ],
          [
            'fred',
            'barney'
          ],
          [
            'george',
            'jane',
            'elroy'
          ],
          [
            'homer',
            'marge',
            'bart'
          ]
        ];
[download]

...roboticus

When your only tool is a hammer, all problems look like your thumb.