I have twin boys that are 4.5 years old in my classroom. I teach a half-day program, so they are with me 3 hours/day. They both wear pull-ups, do not indicate the need to use the restroom, and have bowel movements 2-3x while they are at school. They do not indicate that they need to be changed. I've never had typical students this age not toilet trained (or at least in process). I've talked to their parents multiple times. She has no concerns and says that they'll let her know when they are ready. Thoughts?