So adorable! Great advice from everyone here - I'm going to add one thing. Take her places - lots of places. Expose her to every kind of person, vehicle, noise possible. We rescued two pups in the past year and a half. The first was in the spring, so when we got home from work it was light out and people were out and he got to be friendly with everyone and was never scared or shy or timid. My son was playing baseball and later football so he came to all of the games and met everyone. We even brought him to a friend's home on the 4th of July and he didn't flinch at nearby fireworks. Fearless and friendly Henry.
Our second we got in October, and after work it was dark and on weekends it was getting cold, sports were over, so even though we always took her on a walk every single day no one was around and she ended up loving dogs but being afraid of people and noises. Kids on scooters and skateboards, motorcycles, loud cars. If a person talks to me, she'll bark at them. She won't let anyone touch her other than the three of us who live with her. People are still shooting off their leftover fireworks from July and forget it - she is terrified. These are not even anywhere close to us - blocks away. Some nights I can't even get her out of the driveway to walk with me and the other dog. Scared and shy Savannah.
There may be other reasons she is so timid - maybe some dogs are just that way. But I can't help thinking that maybe it's our fault for not exposing her to more when she was a baby. We're getting some training that hopefully will help.
Anyway, all the best to you and your family and hugs to Ruby!