I have to say I think you're missing out.
When DD was turning 8, the queen held a reception for the Irish premier and his wife at Windsor castle, attended by Charles and Camilla. They went along the high street to the castle and DD heard about it on the radio
She begged to go, said as it was her birthday, she was proper transfixed by William and Catherine's wedding as well. So I grudgingly said yes.
I'm Scottish Irish. We aren't fans of Royalty. I was dreading it.
However, once there, we had a great time. We stood next to an elderly, American couple, who were delighted to be standing next to a very talkative, very excited DD. They have her a flag to wave, let her sit on their spare foldaway chair when she got a bit tired (they came prepared, they'd clearly done this before), they even gave her sweets. When it was done, DD gave them a hug and the lady asked to take a photo of DD with them to show their grandchildren, so DD was asked and said yes.
It was quite chilly, and standing around for two hours was a chore, but actually, seeing how happy DD was. They still talk about it now, even though they're the least monarchist teen you'd ever meet.
If you can go, go. Yes it will be a long old day and night, but if your kid enjoys it half as much as mine did then that's parenting done right and a great memory.