Is the UVA your heat source? Normal bulbs don't emit UVB, you'd need a special bulb and fittings for those. You don't need UVB but it certainly has its benefits.
You should keep the heat source at around 32-35C (90-95F) but switch it off at night. If the light doesn't turn off or dim then it isn't reaching and maintaining temperature. I suggest you get a new heat mat (shouldn't be too much, around £10?) these are much better for the gecko, you can keep it on 24/7 and it'll get to temperature a lot better as it's only heating the floor rather than the entire tank.
Some geckos don't use moist hides at all and shed fine, others require the humidity when shedding. I would provide one even if she doesn't use it. It could be that it's new and she's not entirely sure of it yet. As for how often they shed, it depends entirely on the gecko, age, health etc.