FAQ from Ohio DOE including items on early k:



The website indicates that there is no actual cutoff; they are just supposed to encourage parents to apply 60+ days before the school year start, so that the process is more likely to be completed by the first day of school. There is also no lower limit on age in Ohio, if early entering through GT. Though I would be inclined to give geofizz's suggestion some serious consideration. I also saw a model case study on there for K/1 in a single compacted year.

...pronounced like the long vowel and first letter of the alphabet...