Pelusios species tend to be shy. From my experience, they're also not very adventurous in their diets
Try offering a piece of banana every once in a while. As she becomes accustomed to the idea that you=food, she may assume that anything you put in the water is potentially edible. Mine learned by watching the other turtles though, so how well that will work for you I'm not sure, but most turtles figure it out eventually.
Did she have a filter in her habitat at the pet store? If not, it could just take her a while to get used to the one she has now. Water transmits sound better than air, so stick your ear in the water and imagine hearing that 24/7. If you're not used to it, it could take a while til you wouldn't notice it anymore, and until then you'd probably be annoyed. If she's already used to a filter, then I wouldn't worry about it.
You may want to add a hide of some sort to the water though. I had a simple domed tunnel. Something that mine could get under to feel secure, but still allowed access to surface air without having to leave the hide. You'll want to get a mercury vapor light though. A "basking area" isn't a basking area unless they can bask, which means soaking in heat and UVB rays from a mercury vapor light if she's indoors. From time to time she'll sit up there to dry off, thermoregulate, and absorb UVB. Just remember to change the bulb.
