Is her coloring healthy?

Hello all! This is my first post to bare with me if I do anything incorrectly!
So My friends surprised me with a 2 yr old dragon yesterday as an early b-day gift and I was/am truly unprepared! My main concern right now is her coloring, I am not sure if it is normal for her, or if she is just uncomfortable still since she is in a new place.. her tank is a.. 40 gal tank, I have not measured her for size yet but shes a decently sized girl. Her temp in her tank is about 90, I need to adjust the setup and how the temp is measured because I am not sure how warm her basking area is right under her light. I am not sure what type of light it is, it has a heating coil on one side that i run at night and a heating bulb on the other that i keep on during the day. If I need to get this info I can provide it when I get home! She is currently in sand, I am not the biggest fan of a tank being all sand, I plan to do half sand and half reptile carpet to avoid her digesting sand at all.. a basking side and a feasting side once I get the chance to remodel. (She came with her current setup, it is driving me crazy)
ANYWHO back to the point, is her coloring healthy?

Her coloring looks fine to me in that pic. Quite the pretty girl! If your worried about if she is stressed they usually get really dark colored (like almost black in some cases), her beard will get black or some will get little black lines all over their bellies called "stress marks", though they don't always mean the dragon is stressed. Just leave her be for a little while and then slowly start introducing yourself.
Also is she shedding on her ear/arms/tail?

As for her setup, please do change out her sand, preferably all the way. Like you said, sand is a big impaction hazard. Reptile carpet isn't great either, bacteria love it and your dragons claws can get caught and even ripped off. Maybe try newspaper (it isn't the prettiest) or paper towels, or a more long-term substrate is tiles, which are easier to clean.

The ambient temp is 90*? If so it could probably go down a little, but not to bad. Her basking spot should ideally be around 100*-110*ish so she can digest.
Does she have a UVB light? She will need one ASAP, get a tube one like Reptisun 10.0, for a 40gal she would need a 24" bulb w/ a hood. https://www.amazon.com/Zoo-Med-ReptiSun%C2%AE-Fluorescent-24-Inch/dp/B0009YHSWK/ref=sr_1_1?ie=UTF8&qid=1477092676&sr=8-1&keywords=reptisun+10.0+uvb+bulb

If you have any other questions on caring for her, please ask! Everyone on this forum is super helpful.

Makayla