It's tough. DD4 (almost 5) is skipping K this year and going to first. I have some concerns as well. He hasn't been in a full day program, only attends a montessori school for 3 hours a day 3 days a week. So a full day may be a challenge. I don't doubt the academic piece at all...in fact they are definitely going to need to do some subject acceleration. But I do worry about the social aspect, the loud cafeteria, his first fire drill, him peeing on himself (he tends to wait until he can barely hold it and runs to the bathroom...that's not going to work in school). Also I worry about the words that he will be exposed to that he does not at all know and has never heard. That's frightening to me. But I still can't imagine him in K and know that would be a nightmare. For us I think skipping K is the better choice, even though it's not the perfect choice. There really isn't a perfect choice for a kids like him. DS4 is also quite outgoing and extroverted, so we are hopeful that he will be able to jump right in there. Only time will tell....