J.D.
It's perfectly normal for a child that age to declare her independence. She's growing up. Just let her make some decisions, but don't change her bedtime routine, etc. She still needs consistency and boundaries. As a matter of fact, she's pushing the boundaries to see that you're still in charge and love her enough to keep her safe, healthy and happy. Good luck! It's not called the terrible twos for nothing. Just wait until she's three!!! :)
I just thought of something else. Is she feeling alright? Getting her two year molars? Children can change their eating and sleeping habits when something is bothering them.