International schools and the age restriction (Addis Ababa)

Hello internationals!!!,
Will be relocating to addis with my hubby who was transferred there and my 3 kids (7 yrs and 2+yrs(twins) ),however,I require advice from the community on the very best international schools that communicate in English language( as that is my kids' first language) and also to enquire on the idea behind the 3yrs old restriction for being accepted into the early year stage,as my twins who'll be 2yrs and 5months by August will have 2 sit at home for another 7months before resuming school?
Please,help with ideas as they can already count from Protected content read from A-Z and sing a lot of nursery rhymes and also color and recognize their shapes and primary colors too. I'm in a dilemma as I don't want them to sit at home doing nothing when they've been in school since they were 18months.
Help!!!!!!!!!
Kamara...