I know she is ready because we have days that are very promising, like yesterday. She went potty at school, at daycare, and at home before bath time. Because of that she got a big prize:

Aren't they adorable, I love them and want them for myself!!!
Then today, she did not go pee in the potty simply because she didn't really want to.
Mama Bear: Did you go potty at school?A conversation during bath time:
Baby Bear: I don't go potty at school?
Mama Bear: Why not?
Baby Bear: I no go. sorry. I don't' want to.
Baby Bear: I go pee.Thankfully, it was the end of the bath and so I just took her out. As a friend told me, at least she didn't go poop in the bath.
Mama Bear: oh no, you go pee in your bath?
Baby Bear: (smiles) next time I go potty in the potty. Sorry. Next time. I promise.
I guess when she really wants to go she will go. Hopefully I can convince her to go pee in the potty more regularly. She is definitely capable, she just needs to actually want to do it.