Colossians 1:17 He is before all things, and in him all things hold together.
Christ has been with us from the beginning and will be with us through the end. Everything exists because the Trinity has deemed it so – Jesus being part of that Trinity.
Despite His comparatively short life as a human being, Jesus has and will always exist throughout time.
But, He took time out to come to earth as a human, to live and die as one of us, so we can have a perfect sacrifice given to cover all of our sins, once and for all!