The prices look accurate for the number of points you are buying. I do not think its too late for you to become part of
DVC if you know that you are going to visit every year and will find value of staying on site.
In terms of UY, be sure that a Feb UY will work for your travel plans. When buying direct, guides will simply suggest the one they are pushing at that time, but you can request any UY that you want.
If you have a specific time to travel, you want a UY to start shortly before that because it gives you the most flexibility if you have to cancel or change a trip. When you can travel in your banking window---first 8 months of the UY....it is ideal when things happen.
If you are going to regularly travel in Dec, Feb UY is the worst one to have. Many people will buy direct at the minimum level and add on more points resale. However, any resale points bought now can not be used at RIV, VDH, or presumably any future resorts, which may include Poly tower and FW cabins.
Even owning direct points doesn't change this. Since you are considering VGF, they would be good there, and all the original resorts, just not the new ones. It may not matter for you, but it is important to be aware!
I would also make sure that your will be able to secure a DVC reservation for December as part of the deal. December is very popular and at this point a lot is booked up...but, new owners are given a chance to get a Welcome Home visit and while it may not be at the resort of your choice, they can usually find you something from inventory DVD has access to with the points they own, or for rooms not yet declared for DVC use (like RIV).
Good luck!