As already said you can feed a list to form an hash directly. But note venoth.ree added use warnings (and use strict too: never miss them) infact if your list is odd you can trap some unwanted behaviour:

perl -we "my %hash = @ARGV" Andy 1995 Sarah 1990 Sam 1992 UNEXPECTED

Odd number of elements in hash assignment at -e line 1.
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If you want to build the hash using a loop (ignoring odd element if present), you can use while as in:

@ARGV = qw( Andy 1995 Sarah 1990 Sam 1992 UNEXPECTED );
my %hash;
 
while (my $key = shift @ARGV and my $val = shift @ARGV){
   $hash{$key}=$val
}

# hash is: ("Sam", 1992, "Andy", 1995, "Sarah", 1990)
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UPDATE you can spot the odd element before entering the loop: print qq(odd element $ARGV[-1] will be lost!\n) if @ARGV % 2 > 0; though.

If you want you can also explore List::Util pairs function: it warns on odd element assigning undef

use strict;
use warnings;
use List::Util qw(pairs); 
@ARGV= qw(Andy 1995 Sarah 1990 Sam 1992 UN);
my %hash;  
for my $pairs (pairs @ARGV){
  $hash{ $$pairs[0] } = $$pairs[1];
} 


Odd number of elements in pairs at -e line 1.
# hash is: ("Sarah", 1990, "Andy", 1995, "UN", undef, "Sam", 1992)
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