What about quality of life? There really has to be a balance between work and play. Besides, "retirement" is a recent concept (post-Depression/WWII). Prior to the 1930s, most people worked until they dropped. If someone is counting on retirement, then by all means prepare for it. The argument between the grasshopper and ant approach is as old as Aesop. Most of us are not mature or disciplined enough to be ants though and must find a happy medium between the ant and grasshopper. Crickets still have fun but we stay within our budgets and, aside from some thought to the future (such as a work supported 401K plan) don't spend a lot of worry on a retirement that may never come to be.
To me, if the OP is even questioning the resources for a Disney vacation then she probably is wise to wait. As an alternative, what she might consider doing is pushing her trip out a year or two and start the actual planning. There are a lot of great ideas on this board alone for saving up for a trip. By making a planning strategy, that will make the trip more "real" and the entire family can really focus on planning and saving. This way, she can also set milestones. For example, save first for the hotel stay. When that sum is reached, book the hotel. It's a slow way to achieve the dream but it also keeps the dream from breaking down into the "we'll never get to do this" stage.