E.P.
You may have been potty "training" her for a year but she isn't "potty trained" if you still are having pooping issues...And she might not be for a few more months. Some kids get it while other kids get nervous because of all the pressure that is put on them (i.e. punishment). I know it's frustrating that you feel she's so close and your other children may have been easier to train but.....she may not be able to control this - even though she appears she can. If she doesn't start preschool this year, it's not a terrible thing. Just make bathroom time calmer, read a little, rewards given even for trying, make up a little song...anything to keep her feeling that she is succeeding. If she has a bit of a pattern for when she has bowel movements, you may want to consider sending her, but you are taking a chance that she could have an accident. Keep in mind, even those that have graduated potty training sometimes have accidents. I've seen kids have accidents in kindergarten and even first grade. Good luck.