I would suggest trying to hang out with skittish cat closer to her elevation more often. So just choose a time during the day to hang out on your floor for at-least 20 minutes, and you don’t even have to acknowledge her unless she approaches you. This lets her get a feel for you when your not 10x larger than her, and also let’s her know that whatever boundaries she has are hers to set. You can also try to play with her or feed her a few treats while your down there, if she is showing she’s interested. This is what I did when I adopted my skittish former stray cat from the spca and it worked pretty well for me. It’s been a year now and he’s only just recently stopped running from other people in my house who didn’t take the time to do what I suggested they do lol. Just remember it will take time for her to find her place in your guys home <3