2 going on 16

So lately andy and I have been trying to teach Evelyn that big girls go potty in the toilet. We have also told her that if she does go in the toilet we will have a potty party. Well Saturday night she peed in the toilet and we were all so excited. The next morning we had a breakfast potty party with a big breakfast. Now at night when we are putting her to bed she asks to have a party and listen to 'gaga' Which is lady gaga. She also keeps saying 'whatever' with tons of attitude and when we ask her to do something she sighs, breaths out "fine" and slouches away! My baby's a teen already, what happened!?