Oooh... while reading this thread I thought of so many things I want to post... where to begin...
First, Welcome.
Second, Good Luck.
Third, I was going to mention that some states don't allow you to buy timeshares from that particular state, so you would need to travel to WDW to do it, but Massachusetts is not one of those states. So you are all set.
Fourth, I predict, as others have, that you WILL end up going more than every other year and will add more points. We started with 210 (the mininmum at the time) and are now up to 500. When you have the points and an annual pass (which is what a lot of DVC members use) going to WDW (especially from Massachusetts) is so easy and affordable.
Fifth, Even though using points for the cruise is not the most efficient use of the points, we do it every few years. We figure we have them to use and it is a wonderful change from staying at WDW and why not. Some people rent out their points and use cash for the cruise, and we might try this someday if we can find a really cheap cash rate for the cruise and if the trouble of renting, etc. seems worth it.
Sixth, It is usually not a problem getting a non home resort at 7 months, as long as you are a little flexible. What we do is make a reservation at our home resort at the 11 month window, and see what is available at the 7 month. This past year at about the 5 month window, we had a choice of VWL or BCV for early Dec (actually, we reserved BCV but went on the waitlist for VWL, which became available in about 3 weeks).
Seventh, some people say that this was a difficult decision to make and like you, they got cold feet, but it wasn't for me. We walked in with checkbook in hand and walked out as DVC owners. We NEVER regretted it for even ONE SECOND, and we are reassured every time we check into OKW, unpack and realize we are HOME again. Unless buying into DVC is going to cause you to worry where your next meal is going to come from or cut into your mortgage payments, then be confident that you are doing the right thing and that you are making an investment in your families fun, for years to come. ENJOY.