Salaam alykum

My son is 7 i would like to send him to Darul Uloom Zakariyyah in South Africa. When he is bigger.

What is eduction standards does he need to enter. Meaning does he need a high school certifate.
Does he need good grades? Does he need to be hafiz of Quraan before going there?

What age do i have to send him?

If anybody knows pls let me know.

Wls
Muhammad