A basic knowledge of reading and math is necessary to properly learn a programming language. Assuming you have that, Perl is as good a language as any to start with. You don't need to be complicated -

$cash = 10.00;
$chocolate = 1.20;
$bread = 0.99;
$candy = 0.50;
$cash = $cash - $chocolate;
print "I have $cash left.";
[download]

or

for ($i = 1; $i <= 20; $i++) {
    print "I have completed the loop $i times.\n";
}
[download]

My dad tought me BASIC programming at age 9, including use of loops and variable input / output, and it shouldn't be difficult to teach the same thing in Perl.