This is how potty training goes. Once you put pants on they start peeing and having accidents. It takes a while for it to click, figure out how to pull down undies. Is easy when they are naked, but a nightmare once you add in the pants.
Now that you've started, just keep sticking with it! Everything will click for them and become a habit before long, especially if they're already showing signs that they're ready.
Okay, thanks everyone. My friend also told me about the Oh Crap book, too. I think my plan is to start doing pants without underwear while in the house for a few days. I think she has a hard time wanting to stop playing to go potty when we're out.
The book I read (“Oh, Crap! Potty Training”) said to go a whole month before wearing underwear with pants, because their body feels it’s so similar to a diaper that they pee instinctively. I don’t know how true that is, but we tried… until her preschool teacher said underwear are required. Worth trying! Good luck!