I really hope everything goes well for your DD! For our first skip we changed schools so we didn't have this issue and our DD is much older now. We worried about how she would be received but it was a complete non event and just accepted.
Maybe your DD can just shrug and say"I did some tests and there is where I am supposed to be." The less fuss, the less said, the less drama it will be. Hopefully you will find most kids are nonplussed, especially if she just gets on and does her work and they see she is indeed where she should be.
Good luck!