Female black lab

Question
I bought a female black lab when she was 9 weeks old.  She is very smart and listened well.  She would come, sit, and lay down when told.  Now she is 12 weeks old and wont listen to me at all.  I do I get her to obey me again?

Answer
You need to work with her every single day. The puppy is testing you just as a small child does... officially, "cutting the parental cord". Get her into obedience classes and start practicing "Nothing in Life is Free" with her. http://k9deb.com/nilif.htm  

Instead of plopping down her food bowl every morning, use that kibble for her training treats. Training is best done in several shorter sessions each day rather than one long one. She will be entering her "flight period" shortly, so be sure that you have her on leash when you take her outside of the house or fenced area for the next several weeks.

http://britmorschnauzers.com/critical.html

Also get the book "How to Raise a Puppy You Can Live With" by Rutherford and Neil. You will find it quite useful.