John 1:3 KJV All things were made by him; and without him was not any thing made that was made.
So obviously Christ being God preexisted before the universe and his incarnation as a man and it was His choice to manifest Himself as a human so He can show us how to live. If you don’t believe God has the ability to do this then you have a problem.
Isaiah 44:24 KJV – Thus saith the LORD, thy redeemer, and he that formed thee from the womb, I am the LORD that maketh all things; that stretcheth forth the heavens alone; that spreadeth abroad the earth by myself;