Expanding on Yu Asakusa's answer..
This is something that happens over time, some sites have been in public beta for months and longer, we haven't been up for 2 weeks yet. We also already have alot of content and our userbase is expanding nicely, 300 users so far. I wouldn't worry about it too much as we have already been planning ways on promoting the site. See How do we promote our site? and Migrating Blender related questions from other SE sites?.
However, as an answer to your question, if we don't get enough content or our visits stay low and or users are inactive, there is a high possibility that the site will be closed, but as I said, so far its early and the site has alot of potential. Also, one factor isn't really enough to determine the fate of a site, it usually is based on several or more problems. We will graduate when the community moderators deem us ready.
See How can we ensure Blender.SE doesn't share 3DGraphics.SE's fate?
On a more positive note, we are well ahead of the other site that was closed. The stats look pretty good to me so far.
Here is where we would be in trouble.
We are already way past where they were closed so our stats are pretty ok at the moment.