Hello not sure if you will see this comment now as your post was from a while ago but it came up in my feed. https://www.instagram.com/ready.for.school?igsh=dnBma3Zxd2ZwbTVm&utm_source=qr If you’re on Instagram I’m sharing lots of advice on here about helping children be prepared for school. Hopefully it could help you and also reassure you 🥰
Wrt starting school - Look up the things he is expected to be able to do before school e.g. use the toilet by himself, putting his clothes on/changing, feed himself etc. Get him used to leaving you if that is still an issue. (Get used to you leaving him).