How long will it be until humans colonise the moon?
We need a reason to do so. If a meteor, 500 meters in diameter, 10 times the diameter of the one that made Meteor Crater in Arizona were to strike the Earth, its impact would be 10 X 10 X 10 times as powerful and create such havoc that the largest countries just might band together to establish a Moon Base so as to be able to detect and deflect the next such meteor header at Earth. Barring that, we probably have to wait until we want to manufacture somethings in large quantities that require, say extreme cold and an excellent vacuum such as exists interior to craters on the Moon.
My guess is 5000 years from 2018.