According to me kids should be sent for schools in early age as it will help them to familiarize with outside environment, this can be done by staring with half day schools for them and rest of the time they can be at home.
First to began by attending school early kids will mature fast as they will meet different kids and make new friends. This not only will help them to socialize but also increase their confidence as they will be alone and they needs to do so many things by themself such as class activities, eating. I still remember about myself when I started to go school, firstly I was not happy about it but after awhile I always get excited about the school as I loved spending time with my friends and learning new things daily.
Furthermore, This not only help kids to understand about the routine but also make them disciplined, for example they must get up early in the morning and get ready for school, if they fail to do, this will cause them to miss their school. This small things in early stage will became a common activity in their life and chances to success will be much better than others, this can be anything from getting good marks in exams or winning in sports activities. This also will help them during the hostel time as they are familiar with different people and knows how to take care of themself