Did she show signs of readiness before you began trying to train, like an interest in sitting on the potty, knowing the words for pee and poop, taking off her diapers, staying dry an hour or two, etc? Or are you trying to train her so she can go to preschool in the fall, have a new baby on the way...? Is the training intense or laid-back?
I'm not saying you can't go back, of course you can. But as you said she was making progress, so it WAS working, and I would keep trying. Sometimes they (toddlers) decide the novelty has worn off and want no more to do with the potty, but if you persevere they relent and go with it. I know the "if they're not ready they won't do it" theory, and I accept that to a degree, if they show signs i know they're ready. Control and knowledge will come.
I plowed through with my first son, at the same age as your daughter, who wanted to play rather than sit. He tried to demand his diapers (!) so I put them out of sight, then got rid of them. He wore underwear by day, and at night thick training pants and waterproof covers. And he learned.
My little guy now is 26 months and while it may seem early for some he has gone #1 every day, pooped yesterday and today and is on Day 5 of training (so maybe tomorrow the cookie crumbles, lol.) He did have an episode of trying to hold his poop today when he obviously needed to go, so I pressed down on his thighs firmly enough to spread his legs apart a little so he couldn't clench and he pooped immediately, and thankfully was very happy about it. (I have read enough on this site to know I don't want him developing habits that will cause him severe pain, trips to the doctor and having to rely on laxatives.) He is wanting to play when he should be sitting, so I sit with him and return him to the potty. I give him books, or put a DVD on and talk to him to distract him from focusing solely on the potty as I want him to be relaxed. He's thrown some tantrums, and I put him in his room for a couple of minutes (tantrums earn a time-out) and when he's done I return him to the potty so he doesn't think he's won the power struggle. And when he woke from his nap today HE asked to sit on the potty : )
Taking off the diapers, beginning training and never stopping is one philosophy. If you have the stamina to hang in there I say go for it. You don't need to force her, she may not go for a few days, but the consistency will show her this is how she now goes. If you prefer to wait, wait. If you're not happy she'll pick up on that. I wish you a successful adventure!