Hi
No, don't cancel your order, they are very beautiful geckos and I think that you would enjoy it.
Go to the store and buy some of that nice background scenery paper and put it around three sides of your tank and that will cut down on the light that goes into the tank. When it is time to feed your gecko, you could always take a towel and cover the front of the tank and the lid a little to make it darker in there while your gecko is hunting for it's food. Just leave enough of the top uncovered so you can put a dome light with a black light bulb there to give it some light for hunting.
As far as holding it, you could take it out of it's tank to hold it and then go into a part of your house that doesn't have a lot of light coming in from the windows, or you could stay in your room and pull the blinds closed.
TLB