Is there a cheat that ages up sims?

testingcheats on
and then
cas.fulleditmode
and age them in cas via manage households?

No idea is it fastest way, but only really fast way I know :)

ETA: I am not sure does it even need the testingcheats on , now when I think of it.

just make a birthday cake...sims can age up whenever with the birthday cake doesn't have to be their birthday or even close to their birthday to have them blow out the candles and age up.

I don't know of anything that will age up Sims that isn't one Sim at a time, unfortunately. You might find it fastest for doing *all* but Elders to work through Manage Households.

Ellupelluellu is right on the money!! Aside from using a birthday cake, that's the only way I know of aging up Sims quickly.

Just be aware that if you age them in CAS, their new life stage might not start from day1, but how far into their current stage they are. At least that was how it worked when I aged most sims in CAS. One day an elder died on his first day of elderhood, because the game thought his stage was full already.

So, these days I only use the cake. One cake can be reused if you add new candles before anyone grabs a piece.