Right Time to Start Playschool

My child will start playschool next month. I’ve faced a bit of criticism from the older members of the house for enforcing school on him so early.
“He’s only two. You started school at three and half and you are doing well in life. Let the child enjoy at home. Why do you want to torture him?” my 85-year-old grandmother thundered at me.
Though I do respect and often go by elderly advice, I am not going to alter my decision this time.
Firstly, because I think my son would definitely benefit from being away from the secured and comfortable environ of his house for a few hours (actually, only two) every day.
I want him to mix and mingle with other children his age. At home, he is the center of attraction all day being complimented and applauded for every single act. His grandparents more often than not succumb to all his tantrums. Since there is no sibling around, there are not too many occasions on which he has to even share his belongings.
I guess by going to school at least a few of these things will change. He will play with toys in school that he will have to share with his classmates. He will have to stand in a queue for his turn. He will have to excel to earn appreciation that comes so easy at home.
Though I do know that the first few days will be difficult on him, I am sure that he will adjust and love the place soon. Adjusting to a new environ is difficult even at three and half. He earlier he starts liking the concept of fun and learn the more he will enjoy his school life.
Most importantly, if I go by the pace at which he is grasping language and learning about the things around him, it is quite the right time for him to start some formal and disciplined training.