We got married in mid January as I was starting my first teaching position 2 weeks prior. I took off Thursday, Friday, and the Monday afterwards and DH and I went on a mini-honeymoon in Ruidoso and took another vacation a year later to Vegas. I don't see why a principal would get upset over it. Your kids will get used to your last name. If you have enough sick/personal leave days, you should be able to take a couple off without a much of a hassle.