Actually, arrays don't always start at 0. If you set:
$[ = 1;
... and arrays suddenly start at 1. However (depending on what Perl version you use) $[ may be global, so set it in one place, and other code in distant modules will start acting strangely because they expect it to be set to 0. It has been made safer over time, but is still confusing. For that reason, $[ is being phased out in recent versions of Perl. 5.16 will drop support for $[ from the core code, but bundle an arybase module that implements it.
Either way, avoid $[.
Anyway, even if you prefer 1-based arrays over 0-based arrays, it's not a great idea to use hashes as an array substitute. For many cases (including this one), hashes are quite a bit slower.