C.
What about an incentive to stay on the potty maybe? Juice worked REALLY well for our first since that was the only time he had juice. Our second is 21 months. He'll sometimes tell me when he needs to go potty, but then I tell him lets go sit on the potty and he quickly says no. He doesn't want to be interupted from playing, but recognizes when he's filling his diaper. But since your daughter is willing and excited to sit on the potty, maybe an incentive to stay on the potty would work. Something that takes a while, like sipping juice from a cup or if that's not incentive enough for her, maybe a lollipop or popsicle. Just a thought.