They received my application on 02/09/09 but for me the 90-day rule started on 02/17/09, and while I was expecting USCIS to mail the application back they didn't. They waited until 02/19/09 to cash the check and mail the priority date (02/19/09 so 88 days before the 5-year requirement) so although they didn't reject it, everything is within the appropriate time. And my interview was today so exactly one day after the 5th anniversary of my permanent residency.
Did they recommend you for approval after the interview? Have you received oath letter yet?