If you have some hesitation about the financials, and with three little ones, there might be good justification for waiting until it feels like any other decision would not be the way to go (when your gut says it's time to buy, as well as your brain).
I just bought a couple of years ago when everything was looking rosy for me, but things have changed and am now thinking I might have to sell my points next year, if things don't take a major change for the better.
Why I decided to buy included our having gotten used to travelling differently having gotten into timesharing a few years ago -- it is SOOOOOO much nicer than the way we used to travel. And, as I am getting older, being on property started to have more appeal, so we wouldn't all be tied to the same mode of transportation and schedule (if I want to take it easy and loaf on the balcony or at the pool, and the younger ones want to hit a Park or go offsite, it will be much easier to split up).
With three youngsters, if I could really safely afford it, including all the additional and accompanying costs, I would say go for it -- it would be wonderful to have that enjoyment for at least awhile. DVC does maintain at least some resale value, which most other TS systems do not.