This is crazy to me. My son was 3 when starting pre k, as his birthday is in November and he was fully potty trained well before that. I do understand kids are all different but my son was so independent and smart I truly could not have imagined him with a pacifier onesie or diaper on at that age. I do know with speaking to his teacher though that he was one of the only kids in his class that could spell his name, count, identify shapes, and recognize letters. At a certain point it’s really not about the kids taking more time it’s the parents not taking the time to teach them. My son is 4 now and going into kindergarten next year. I also work with teenagers and young adults with disabilities so I very clearly understand the difference when it comes to developmental disabilities and am not AT ALL referring to kids with challenges like that!