When she needs to she does. When she needs help she asks. This isn't neccessary when they are ready. A time will come, naturally, when your child will toilet independently. I like what Barbara Colorossa says about toilet learning and other things - treat a child how you want to be treated in your old age.
People deserve respect at every stage of life.
Keep trusting your child. I am much more relaxed about it today. My dd will use the potty consistantly if she is naked, pee and poop, but not if she is wearing any clothes on her bottom half, she will just pee in her panties. She knows how to tell that she has to use the potty, she knows how to use the potty, but she's not totally ready to train because she still doesn't care if she uses the potty. My son still isn't poty trained but he has begun expressing more interest since we got him a toilet seat for our toilet instead of the potty.