Newbs are okay. They may make a mistake once in a while, but it's okay, because they're new.
n00bs are not okay. They flagrantly make errors and may/may not pass it off as an age thing, or a 'sry i din read teh rulez' thing, or a language barrier.
1.) It's okay to write something in less-than-perfect English, esp. when you're speaking it as a second language. Just as long as the content is there, then you have nothing to worry about outside of the random grammar nitpicker.
2.) It's okay to accidentally make a dumb post every so often ... We all fall prey to idiotism at one point or another.
3.) It's okay to make a small rule-breaking mistake once in a long while, as long as you don't do it again.
I don't care what age these people are. If I know they're 12, I'll assume they're going to make a few juvenile posts, so w/e, no big whoop. I was 12 once. Kids are dumb, even if they try to believe they're not. Not a big deal. But I WILL assume that they have atleast a tenuous grasp on the English language and can make a point. So yeah ... Age is not an excuse.
sry