Just to clarify my comments, there's obviously nothing wrong with investing your money. And I don't think your age really plays a big role in this. You probably should give SOME consideration to what the future holds since you don't want
DVC to keep you from accomplishing other goals, but you know that situation better than any of us do.
But with regard to my other comments, here's what I was trying to say: If you are a Disney cash guest, it's very easy to skip a year (or two or three) as your financial situation dictates. If you are a DVC member, you are not only obligated to pay more than $200 per month (figure $150 mortgage plus $50+ dues for the first 10 years), but then you also need to come up with THOUSANDS of dollars for transportation, tickets, food, souvenirs, etc.
Here's my abbreviated DVC history. We first became aware of DVC back in 1997. At that point it seemed a bit of a stretch so we passed. As much as we enjoyed WDW, we didn't make it back until 2002. We finally became members in 2003. Many people will say "I wish I had done it sooner", and buying in 1997 certainly would have saved us some money on our points. But doing so would have meant other sacrifices in our lives--sacrifices I'm glad I didn't have to make. The years between '97 and '03 featured some major events including buying our own (first) house, paying off school loans, wife changing jobs, wife staying home to take care of the kids, and so on.
I know it's hard to do, but give a lot of thought to where you want to be in the next 10 years and consider what sort of financial sacrifices you may have to make if you have about $4000 per year committed to Disney and not available for things like wedding expenses, house down-payment and/or repairs, or expenses associated with a new child.
Also, I can't help but notice that your Disney stays have been at Value or Moderate resorts. Financially, you will probably find that over the long-haul the best you will do is break-even compared to the cash cost of a Moderate resort. Staying at a Value will ALWAYS cost less. You may be looking at this as a way to upgrade your accommodations to Deluxe-class, and that's fine. Just be aware that you probably won't save any money while you are upgrading.
Good luck in your decision.