The school should have well trained, learned and able teachers in English, Mathematics, Science etc. If your children study in such schools, they shall acquire good knowledge in each subject and shall excel academically. There are many schools in town. But there may not be good teachers for all subjects. Even the available teachers may not be good and they may not be devoted to their profession either.
Many children study in such schools.
Such children may not be good students having any deep knowledge in all subjects. However hard they may try, they may not be able to reach the top level. For all of us to come in the unity of faith and of knowledge of our Lord Jesus into a perfect man, and for perfecting of the saints for the work of the ministry, for edifying the church which is His body, He gave some apostles, some prophets, some evangelists, some pastors and some teachers. These are the ordinances God commanded for us to grow spiritually. If not, you can never grow spiritually.