tcw,
You kind of already answered the question, as you said in your post that you didn't feel you were quite ready yet. No problem with that, just keep practicing until your confidence level improves.
As far as a "standard" goes, I agree with what most have said about consistently being able to put your arrows in a kill zone size target at a specific distance. However, something to think about here is that nobody mentioned a specific distance. As an example, you don't have to wait until you can consistently put your arrows in the kill zone at 20 or 30 yards. If you're confident with your shooting at 10 yards (or 5 or whatever), I say go hunting! Just do not take a shot beyond your comfortable distance (however long or short that might be). That's what it's all about, knowing your personal limits and sticking to them. We're given a finite number of days to witness sunrises in the woods, so enjoy as many as you can!
Brad