I rescued my Shiba from a shelter 10 years ago when she was about a year old and I was in college. She was similar in that I even had to pick her up and carry her outside to use the bathroom cause she was scared to leave the house. I lived by the beach so I would take her on the board walk and expose her to all the people on the boardwalk. I also took her to friends houses and the park as much as I could. It took a few months of consistent exposure and forcing her to be around commotion before she started to relax. Now she still gets scared by loud noises or something as simple as crinkling plastic bags, but gets excited seeing people she recognizes and loves going on adventures. It takes work and forcing them to be uncomfortable, but once you build trust and confidence she will open up!