Everyone’s age is biologically halved. How does the world change?

At this moment all humans have their age biologically halved. World leaders are now young to middle aged adults, militaries are now kids and young adults, and the world’s oldest person is now in their late 50s. How does the world change as a result. The person health is what it was when originally that age but everyone keeps their memories.

Pregnant people find themselves holding a newborn. So no babies or new mothers dying.