My dd was trained at about 40 months old, just a couple weeks before the start of preschool (which required the children to be potty trained). We were really under the gun. Cold turkey method - we were at the store, buying diapers, and I said it was the last pack, that starting Sunday there would be no more.
It took about a week for her to be trained. Unfortunately, being as strong willed as she is, she went the entire first day without peeing (about 12 hrs) and then I put a diaper on her for bedtime (in which she immediately peed and pooped). So the nighttime diapers had to go. It was summer so a lot of the daytime was spent outside; we brought the plastic potty out there. Plenty of nakedness.
The horrible thing was that she ended up with a UTI from holding it so long. We didn't realize that until later, the following week, after she was already trained. So I felt pretty bad about that. (The only alternative was not going to preschool. Due to her speech issues and the fact that I had newborn twins at home, I decided preschool was very important for both of us).
By the way, this is the same girl who, when she was a baby, the ped called the most strong-willed baby he had ever met. (long story....)
I later used the cold turkey method again with the twins when they were about 36 months. Since they were less opposed to the idea, it ended up working well. (except that it was indoors in cold weather; they stayed naked from the waist down for about a week; thank goodness for hardwood floors.)
My advice would be to lay off until it's absolutely necessary. Is she in any kind of programs with other kids? Sometimes peer pressure works wonders.
