And because time circles, He already exists. Always did, always will. The Universe is safe. Thus God must have a Human stage. For all life goes through all the stages of its specie's evolution as it matures.
Babies start out as single celled creatures.
Later in the womb they grow gill slits. These turn into part of the neck. They crawl at first on all fours and only later become bipedal. Christ recapitulates God. Because we grow into the head which is Christ.