Wa `alaykum As-Salamu waRahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
1- Islam stresses the importance of education as a religious duty.
2- Boys and girls can share classrooms as long as they abide by the guidelines of male-female interactions.
In his response to your question, Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
There is nothing in Islam that forbids girls and boys are sharing the classrooms as long as they conform to the Islamic guidelines governing male-female interactions.
Men and women used to share public spaces including mosques and markets during the time of the Prophet (peace be upon him), and there was no concept of physical partition.
Islamic guidelines in this regard above all stress modesty and shunning of undue display of charm eliciting lustful stares and advances.
As long as these guidelines are observed, there is no reason to ban co-education.
Allah Almighty knows best.