I would say not ready if she doesn't know when she needs a wee.
When they recognise before they need to go and can hold it to get to the toilet, it's so much easier.
Other people do it differently though, taking them the toilet frequently, reminding them to go, bribes/rewards for going, having bare bum/just knickers on.
I found with mine that when they were properly ready, I didn't have to remind them to go, didn't have to carry a potty/spare clothes anywhere, no accidents.
The biggest thing though was self motivation - so no bribes/rewards needed as they WANTED to do it so going on the toilet and wearing no nappy was the motivation rather than a toy being the motivation if that makes sense.
All children are different though and lots of people have success with other methods. I just couldn't face loads of accidents!
I found being able to wee on demand was a big indicator of being ready as it shows they are aware of which mussels they need to use to go.
I didn't have a potty, just went straight to the toilet.
Does she tell you as she is weeing in her nappy?