The right age for baby go to school.

hi,im a mom of 1 baby 14 months boy. can i check with any other experience mom. What is the best age for our baby to start their school? I have school offering my son to join playground at 18 months. But im in dilemma whether it will be too early for him to join full time school. We do have helper at home who take care him always. Kindly need precious input from all other experience parents