As already stated,
DVC is a personal choice and fits the needs of everyone differently. How often are you going to go to Disney? Do you want to be tied to
Disney vacations for a long period of time? Do you usually stay deluxe resorts now? Or, are you looking to be able to stay at deluxe level resorts in the future. We bought in in 2009 since we were going yearly, staying at deluxe resorts and realized that we would continue to go to Disney for years to come, even once kids got to be adults, because, frankly, I love the place. Fast forward to today and I am the proud owner of 800 DVC points with plans to visit around 8 times a year, sometimes even by myself...going on my first solo trip starting today. I look at all we have spent in our DVC, including what I spend yearly for MF's as my way of supporting what makes me happy as I start my retirement.
Had it saved me money? Nope. But that is because I go a lot now vs. just that yearly trip. However, I love that I can book what I need, when I want and don't "feel" like it is costing more than my MF's now. Do I know that I spent a lot to buy? Yup, but again, it makes sense for my situation.
To OP, consider when you are going, how far out you will plan, and if you will be happy owning DVC, and feel comfortable with the financial burden DVC will become for you. Buy where you don't mind staying, unless you won't ever book more than 7 months out. Of course, DVC is getting harder and harder to book if you are not a planner, so be sure that you can book your vacations far in advance. When I first became a member, trading out at 7 months to other resorts was pretty easy. Booking trips 5 to 6 months out, other than December, was doable. Now, if you don't book October to January right around 11 months, it is tough getting more than a few nights here or there. 1 bedrooms seem to be the last to book up so getting that at places elsewhere can be a bit easier than the other room types. If you feel buying 100 points direct at OKW makes sense over BLT resale, then go for it. Remember, the long cost are MF's, not initial cost. Plus, starting with less will give you a feel of how well DVC works for you. While we have been fortunate that resale value of DVC has held vs. other timeshares...I have sold contracts over the years for more than I paid, even after commission...but one should not even consider that, IMO, when buying.
Good luck!