You might try meditating on the following:

1. You don't know anyone else on the site, or if you do they aren't going to change their opinions of you based on it (unless you do something /really/ rude).
2. You feel fairly competent about yourself outside the site
3. If you do something silly today, you can always do something brilliant tomorrow.

This doesn't mean you should start flaming or being rude (remember that intelligent, decent person part). But it does mean that if you make a mistake it's not the end of the world. You'll post again some other time. And having some strangers temporarily think less of you just isn't all that important.

Perl Monks just doesn't strike me as the sort of place where the weight of the world lies in the balance. Worry too much and it'll take the fun out of it.