Here's my timeline to give you an idea of how long the process is. Mine took 10 weeks.
FBI received my request on August 15, 2016.
Credit card was charged on September 26, 2016.
Report was done on October 14, 2016.
Result was mailed out to Manitoba on October 18, 2016.
Date we actually received the PCC was on October 26, 2016.
Good luck. You don't have to worry right now. After your Credit Card has been charged wait for at least 3 weeks to a month before calling the FBI about your PCC. If you call and ask them, they will let you know if they're done with the result or if they have mailed it already.. I called them 9 weeks after sending the application..
Here's a thread where you can actually check other member's application timeline:
http://www.canadavisa.com/canada-immigration-discussion-board/us-police-clearance-fbi-processing-times-t270222.855.html
Good luck!