#!/usr/bin/perl
use strict;
use warnings;

my $string = "hello my * name is Rob * and * I am a very nice person * at least * I think * so";

my $part1 = "hello my * name is Rob * and *";
my $part2 = "I am a very nice person * at least * I think * so";

sub split_before {
    my ($string, $pos) = @_;
    my $pos = rindex $string, '*', 30;
    split /(?<=^.{$pos}\*) /, $string, 2
}

use Test2::V0;

is "$part1 $part2", $string;

is [split_before($string, 30)],
    [$part1, $part2];

done_testing();