The new disease you release upon the world is called MILFvid-19 due to the fact the disease mainly effect people 19 years old and under, and because those infected by the disease end up as sexy women with bodies significantly older then they were before.
Those infected by MILFvid-19 can carry and spread the disease for weeks or even months before start to show symptoms. Once an individual starts to show symptoms their body will rapidly age and become an attractive female adult over the course of a few weeks.(It doesn't matter if they were male or female before they all end up as women.)After the change the subjects body stops aging altogether for years or even decades depending on how much older they were after their change compared to before and then starts up again with no problem. Once the change is complete it is believed the individual is no longer able to carry or spread the disease.
The pandemic caused by MILFvid-19 lasted 3 years and in that time over 160,000,000 people contracted the disease and turned into sexy women with roughly 7,500,000 of the cases in the Us alone, and 3/4 of the total cases being children and teens. No cure or vaccine is ever created and even after the pandemic ended MILFvid-19 continues top pop up in random places around the world for centuries to come.