Oldest child checking in ... an only daughter with 8-12 year gaps between herself and following siblings. While our family destination wasn't WDW -- my folks dragged us everywhere: annual summer cottage rental on the Jersey Shore; church camp at Schroon Lake, NY; frequent visits to Washington, DC (business travel for Dad); roadtrips between NJ and New Orleans (family roots); camping/RV trips across the country; one big trip to Europe; a short visit to Oahu (younger brother marching in band/parade event); and my "last" official family trip to UK.
I was almost 16 during the big Europe trip (3 weeks using only "carry on" luggage, my first "perm" to avoid needing a blowdryer

) ... and somewhere early college for the UK. I do remember the odd significance of the UK trip ("last family trip") and the pains of missing out on a later visit to Europe.
I did quite a bit of work-related travel in my early career and enjoyed racking up frequent flyer miles and car/hotel "club" privileges. My parents had done an excellent job in teaching me to travel! Once married, my husband and I enjoyed "alone time" travel for a few years (I had to teach
him how to travel) ... then, thanks to cruises and timeshare, we returned to traveling with family.
It has been our joy to share vacations with various family members. Granted, my folks are our favorite "travel buddies" (almost a given considering the years they invested training me) -- but we are quite fortunate to have a long list of vacations shared with my husband's family: Big Bear, CA; Oceanside, CA; Big Island, HI; Branson, MO; Grand Lake, OK; Palm Springs, CA; Warner Springs, CA; an Alaska cruise; etc. I surprised even myself last year sharing a 1BR unit with my MIL in Anaheim last year -- we survived!
So ... for those of you facing this "weaning" process with your daughters, take comfort knowing you've raised them well. Enjoy watching them discover travel on their own terms for while and look forward to larger family adventures in the future.