I don't think your criteria is very good. You seem to be saying that whether Perl code is "baby" or "bad" depends on the experience of the programmer. I don't think that's true. "Baby Perl" can be distinguished from "Bad Perl" without asking the developer how long he has been coding.
I think that there are things that mark code as bad. Incorrect code is bad. Insecure code is bad. Code with significant performance problems is bad. Code that is difficult to maintain is bad.
But there can be "baby" Perl (or any programming language) that exhibits none of those problems. It might be simplistic and lacking in idiomatic expression. It probably doesn't use any "advanced" language features. But none of that makes it bad.
BTW, I'd much rather deal with a junior programmer who is writing "baby" Perl (good or bad) than any programmer writing bad but "advanced" code. ;-)
"My two cents aren't worth a dime.";