Magic, People: The Baby Boom
This is definitely player knowledge and NOT character knowledge.

Because of the surplus of magic AND the fertility spell cast on Isadore, ALL mages can have children at a younger age.

The phenomenon will start cropping up more and more as the young mothers start seeking prenatal care and eventually it'll get press coverage.

My thinking is that the fertility spell (cast by the mystery NPC) broke the universal law about fertility which became compounded by the surplus of magic around New Meridian. The result is that the one, very pointed spell expanded and altered the world so that now mages can have children younger (the cusp I would say is 18-19). I don't know what other ramifications this might have yet (considering that mages will be giving birth before their magical gifts are fully realized and before they've had a real chance to discover them). I can already see Salem Academy building a daycare wing to help their young parents get through school.