PamT please don't blame yourself or feel "bad" about your dd still wearing pull-ups at just over 3 yrs. I was very similar in my attitude to nappy changing and don't think it has anything to do with it. Your dd's toilet training readiness has absolutely no bearing on your parenting skills (OR your child's intelligence!) and you MUST not feel guilty or embarrassed about it, or dd will pick up on your negativity and that could cause problems! You must try to remain positive and keep it low-key - as hard as it is to remain calm in the face of puddle after puddle, it is important to try not to make a big deal of it or to blame (or shame) your dd (been there, done that ). Generally children do not have "accidents" deliberately (which is why they are called accidents!)
Please don't blame her or yourself - it would be like feeling angry at your dd for mastering crawling late or feeling guilty because she said her first word later than someone else's child. It is a physical readiness thing and when they are ready to crawl/walk/talk/have bladder control, they will do it! And the muscles that control the bladder and bowel are the LAST muscles in the body that a child gains conscious control over.
My ds was very similar to your dd in that he was very excited about the whole potty idea for a while and it was a bit of a novelty, but then he decided he'd rather go in his nappy again. Having learned the hard way with dd that pressure would only make it worse, we dropped the subject completely until he instigated it again (at 3yrs 2m). Once he had a few successes, we put him in undies (during school holidays) and he was off and racing! We did use a sticker chart and lollies (the latter is still an issue unfortunately, but they definitely provided the motivation he needed!)
To kiwibird, sounds like your dd has done really well quite early. No I don't think she is "damaged" at all - she just had a bad day. Was she wearing something she found it hard to get off/into? Any new kids at the childminders? Is the toilet different there (higher/darker/further away) or does she use a potty? Pull-ups might give her more confidence...as I suggested to PamT, maybe make the whole thing a non-issue for a while, in case it is either a control thing or a "feeling pressured" thing. Hope she's going better now. Please try not to worry (or feel guilty)! HTH and sorry to go on!