There's hacky way to do this with Landslide and Nraas Overwatch...

But first... I remember I released a version of Landslide that can read write the "age" property. But I don't remember if I released this proper or just as a fan edition. To find out type "slider age list" and see if you get values or an error message. I can upload it somewhere if it doesnt work.

Nraas Overwatch has functionality for "alarm commands" which are console commands executed every night.

Here's what you do: Take the lifespan in days for your adult sims... let's say that's 23. Open a calculator and type in 1/23 ... that's about 0.0434782...

the command for landslide would be something like:

slider someslider setto age mult .0434782 if adult

then you register that line in Overwatch as an alarm command. I think that should work. But It will not automatically realize if you change the agespan for adults, you would have to modify that manually every time you change it.