When should i tell dc we are going to WDW?

[dkbnyc]

we are leaving in just over a month for our first trip to WDW. we will be celebrating DDs 5th birthday ( 10 days early). Younger DD turns 2yo 3 weeks later.
any ideas on when and how i could tell the girls we are going. THe little one wont really get it but the older one will flip her lid. I dont want to tell her too early, the longer i wait the better it will be i think.

 

[hvsteve1]

We took our grandniece for her 10th birthday. We told her when her parents walked her into the airport terminal to find us there to surprise her. The reaction was priceless. We got it on video and still love watching.