There ar some levels you have to attend like:
Formal schools have existed at least since ancient Greece (Academy), ancient Rome (Education in Ancient Rome) ancient India (Gurukul), and ancient China (History of education in China).
Obligatory school attendance became common in parts of Europe during the 18th century. In Denmark-Norway, this was introduced as early as in 1739-1741.
Since the school attendance is obligatory still there are some kids who dont have a chance to attend to a school. There could be a lot of reasons for it. In some places the lowest levels of the schools isnt free or at least the price for the books are so high that they cant afford it. And further way there are some differences in the same level of schools. The place can be more different or the teachers and the level what they are teaching.
I think if the school is obligatory from 18th century and we are here in 2019 than everyone should get the chance to attend to at least a primary school and get the same kind of education.