I say wait.
Mine was sent on Tuesday, August 21st, delivered on Wednesday, August 22nd and I got my confirmation today along with the group that sent theirs on August 17th and 18, received by Monday August 20/21st.
Don't feel pressured.
__________________
Application Sent - 08/21/2012 to Chicago,
Delivered - 8/22/2012
Date of I-797 C Notice of Action - 8/24/2012, 8/30/2012 Letter
Date of Biometrics Appointment - 9/26/2012
Routed to: Vermont,
Location: NJ
APPROVED: November 5, 2012