Isn't time out supposed to be easy at this age?

We’re just started trying to use time out with Evie. Yesterday she was pulling on the cat’s tail. I know nothing new, but she seems to be much more aggressive lately. So H decides to put her in time out. He tells her to go to time out. She looks at him, walks across the room and sits down. H has her sit for a minute, tells her that pulling the tail hurts the cat and tells her to say she is sorry. She signs sorry and H lets her out of time out. She was only out of time out for a minute and she is pulling the cat’s tail again.

This time, I send her to time out. She goes and sits down. She then starts giggling and playing. UGH! I tell her that pulling the cat’s tail is a no-no and she needs to tell the cat she is sorry. She looks me in the eye and shakes her head no. I repeat myself a little firmer and she still shakes her head. I say to her she can go to night-night instead. She nods her head.

I take her to her room, turn on the music and start rocking her in the rocking chair. After the first song, she sits up and looks at me. I tell her if she tells the cat she is sorry, she can get up. She signs sorry and off she goes. She not bothered the cat yet.