I followed her opinion and waited for a while before sending in my application. It took me 9 months to get my official GC from the day I140/I485 was sent out last June. I think you better wait until you meet the 3-year requirement. Of course, if you are sure your case can go to TSC, it may not be an issue, however, things could changes pretty dramatically.
Suggestion: consult a good immigration attorney that other people recommended. GL.