Hi and welcome!
Your daughter�s verbal WISC meets the criteria for the IQ test and I would assume with a composite of 21 on the Explore as a 5th grader, at least two of the subject scores also meet or exceed the achievement criteria. Check and check, right?
It sounds as if you are on the fence as to whether or not she is at the level that Davidson selects as young scholars. This could be GT denial or your better judgment.
I was in the same position with my daughter. She tested as almost high enough at 7 or 8 to meet the minimum requirement with a verbal score of 144. I know she is GT, probably the chameleon, perfectionist with a good dose of well compensated LD (auditory processing) variety. We have not pursued Davidson for her because she seems less intense than her brother who has been in DYS for awhile. I think the benefits have definitely spilled over to her as well, so I have no regrets.
However, if this is the only child in the family that you would consider for application, you should take some time to reflect on each question and see how it turns out in the end. Start looking for some evidence and if you think the finished product is strong enough, send it in. This is what I would do, if I decided to submit for my daughter. Just for contrast, I filled out the application in a very short period of time for my son as my biggest problem was to narrow down all the examples that came to mind rather than trying to think of something that fit.
Either way, you can gain a lot of knowledge and resources from hanging our here. I sure have.