I agree with everyone that she's probably becoming more familiar and comfortable so now she feels she can see what she can get away with. Bear was the same way, quiet, well behaved practically hid in a corner and never went on the furniture for about the first 3 month. Now he's stubborn, listens when he wants to and I can't pry him off the couch. Glacier and Jessika are right, try going back to the basics including potty training and a basic obedience class. Make correction immediately for bad behavior and praise and treat when she does something you like.