The first week of school is tough, as they are making their "clicks" so to speak, after that I would have no problem taking them out of school for vacation. If she wouldn't miss the first day, I say go for it. My 10 yr old DD takes a 7th grade honors math class. The teacher her gave her the work before we left. That was the only work she had. The work from her regular 5th grade class, the teacher said "go have fun". My 1st graders teachers response to me when I asked her if she wanted to give us any work was "I thought you said you were going on vacation" what do you want work for. The only thing she gave us was a booklet called "My Vacation Journal" Which turned out to be a lesson for the 1st grade class when DD brought in Pesos.
We went in May, when basically all the work for the year is already taught. We are going back this May also. DD will have the math regents this year, but its not till after we get back.
So Go and enjoy. Only you know if it is the right thing to do for your children. If they are old enough, why don't you ask them how they feel, if they would feel funny missing school that early in the year.
Joanna