God transcends all time and space.
Before He was God, He was the Eternal Spirit [the Self Existing One]. The word god denotes an object of worship. After Angels were created and they worshiped Him, He was God by definition.
God is not His name but rather a title. The mighty Jehovah took the form of man and His name is Jesus. The name of the office titles of Father, Son, and Holy Spirit is the Lord Jesus Christ.