is it possible?

Our Sadie girl sucks her thumb. We tried so hard to prevent it from happening, but the little stinker was determined. It has been nice though. She is easily comforted and has slept through the night since she was 3 months old. I would like for her to be done with it now. I know...wishful thinking. I know of so many people {family included..wink wink} that didn't stop sucking their thumb/fingers until they were 7 or even older. I know it'll happen eventually and I know she has control over it, so is there a miracle out there where a 2 year old stopped sucking her thumb? I should say "thumbs" because Sadie girl sucks both of them. Any thoughts?? we have started telling her, "sadie, please stop sucking your thumb" she'll then throw her head back and start laughing at us. stinker.