She's still there.
My best guess on her age is 3-4 y.o. (possibly as old as 5-6 at the outside--I have a hard time telling with adults, and I didn't get a good look at her teeth).
The shelter's vet put her at 2-3 y.o., but honestly I don't think 2 is realistic for her.
She was completely filled out with a full barrel chest when I met her (she's dropped some weight since then), and made an "adult" impression. The lady who (briefly) fostered her and returned her agrees that she's at least 3.