I will say we are exactly 3.6 questions per day away from graduation at the moment :)
It has happened before that a site has graduated with only 'OK' in some categories, but not in the traffic categories as far as I can see. In that matter, "visits per day" (here we have the 'Excellent' rating), and "questions per day" are the most important ones.
Go ahead and ask questions, folks!
The SE team is seldom announcing a graduation a long time in advance, and it seems like it depends on other factors than the stats too, for example custom design, and simply if they have the time to do the graduation.