The youngest age that I have taken my children to Disney World was when my youngest was just 11 months old. She had a blast and it was such a fun vacation. We did not however go there just for her, she has older siblings who were 2 and 5 at the time. We were unable to ride Space Mountain, Thunder Mountain, etc. but that's ok. We knew ahead of time that we would have to skip those rides. But if you have a grandparent who can stay with the children or you want to ride alone then you can easily make arrangements to ride these rides that have the height restrictions. Surprisingly at just 11 months old my little princess was able to ride many rides and had just as much fun as her older siblings. Would I do it again? Yes. Would I encourage you to visit with an 11 month old? Yes. Would I plan a Disney vacation for just an 11 month old and no older siblings? No. If you absolutely can not wait to experience the magic of a Disney vacation until your little princess or prince is six years old then I would wait at least until he or she is 3. It was a lot of work for me personally to change diapers, nursing the baby and worry if she was getting too hot, etc. The Baby Care Centers are wonderful and I spent a lot of time there. But it was all worth it to see her little face when she met Mickey and all of the other characters. I would never have considered leaving her at home with grandparents and missing out on our family vacation.
11 months old and loving Chef Mickey's!
Meeting Piglet for the 1st time!
She took many naps in the stroller at Disney!