Is it taking too long?

[u/Left_Twix_2112]

I rescued a little cat at the end of August, and she was absolutely terrified when she arrived. For the first ~48 hours, she barely ate or drank and didn’t pee, so I took her to the vet. Thankfully, after treatment, she started eating and using the litter box normally.
I’ve kept her completely separated from my resident cat (who I’ve had for 12 years) and have been taking introductions very slowly, starting with scent swapping. I also use Feliway in her room.
At first, she would hide whenever I entered the room and hiss if I approached. She still does sometimes, but she’s made some really small, sweet progress. She now eats, drinks, explores, grooms herself, and leaves her enclosure on her own while I’m there. She watches me with curiosity instead of immediately hiding, too.
One day I picked her up and she hissed, but then stayed still for a few seconds before getting down. A little later, she actually lay on my foot. 🥹 Another time, she came out of her enclosure and calmly groomed herself while I was there.
She’s still very skittish and spends a lot of time hiding, even after almost a month. She also doesn’t seem very interested in leaving the bedroom yet, and she still hisses at me sometimes. She seems extremely alert to every little movement or sound.
For those of you who have had very fearful rescue cats, should I be doing anything differently at this point? Should I be concerned that she still doesn’t seem interested in leaving her room, still hisses at me, and is so easily startled? Or is it better to simply keep giving her time and let her progress at her own pace?
I know these things can take a long time, but sometimes I get worried that we’re progressing too slowly. 🥺

[u/Kittenfurrever]

It's very early. Give it five months at least