[Flamingo]

DS will be 8 and DD will be 3 when we go in August 2020.
DS can be quite anxious about things so we've learnt from previous experience not to spring things on him at the last minute.
We're planning on telling them on the first day of the school holiday which will be about 3 weeks before we go. Plenty of time to watch rides and waterparks on YouTube, and for me to get the cases out to start packing.
We're going to give them both a small box with a few bits and pieces for the holiday including a countdown chart.