I hear that all the time when we go on our trips but guess what I want to travel and I'll remember it, if I wait till they remember it I might be dead 🤷 not getting any younger.
The new thing you can do now is afterwards, turn the trip into a book for them to look at no matter what their age. Years ago our five yo granddaughter stayed with us for the summer and I made that experience, with pics of all the places we took her, into the “Most Excellent Adventure”. I’m sure she doesn’t remember now all we did, but she can look at the book about her and see it again. Have a great time. It took us to retirement age to get to Yosemite and now I want to plan a trip around the Utah National Parks.