My daughter was almost completely done (including night training) at 22 months. Yes, she is ready. Now, you need to come up with a plan to assist her in accomplishing this goal.
She needs to learn control and timing. These take time, and she will require you to help her learn this stuff. Get her on a schedule, and never ask her if she needs to go. Make it questions like "do you want to go potty before snack or after? do you want to use mommy's toilet or your toilet?"
Great job in keeping her in panties. Now, you just need to help her be successful. After a while, she will be able to take full responsibility for taking herself to the potty. They say that most kids still need help till 3. My daughter is very good about taking herself off to the potty, but they are just so easily distracted, accidents will happen. In fact, I read that you should expect accidents for up to 8 months.
To answer your end question: do not turn back and put her back in diapers. That will just confuse her. Hang in there, clean up the messes, and she will be trained much sooner than if you turn back. Tell her she is too big for diapers, and believe her capable of mastering this very difficult developmental milestone. Be patient, never show negative emotion, and when she has accidents, just say "pee/poop go in the potty."
She is very much ready! She is going on the potty! Just give her the time and space to learn the timing and control. It could take a few months or a few weeks.
Oh yes, and expect regressions, lots of them. For every step forward, you will go back, and then, one day you will wake up and not recall when the last accident was. But accidents aren't signs that they aren't ready, it's signs that they are LEARNING.