Isn't it alreday an international currency? I think it is. Since people around the world begun to use it it has begun global, international currency. Today I think it is used on all continents. Will it be officialy recognized as such, that is another question.
You are right it is already an international currency as we are seeing that none of the country is its owner and all over the world this currency can be used and people use this currency for their international transactions etc.