Being at the lower end of the DIN range is not a problem. In my opinion this talk about how you shouldn't be at the low or high end of the range doesn't make any sense. The bindings are tested to work throughout the entire range. If the binding has a DIN range of 6-14, that means you can run it at 6 or 14 and anything in between. Why would it have that range otherwise?
Also "you don't need those bindings if you're going to run DIN 7" is bullshit. There are other things to consider besides the DIN range. Durability of the binding is, to me, the most important thing. People who weigh less and therefore use a lower DIN setting can break bindings just as much as a heavier guy. Why shouldn't they be able to buy quality bindings?
There seems to be this air of mystery and exclusivity around high-end bindings on NS. Like you have to be Seth Morrison to use them. For example every time someone asks a question about FKS180s/Pivot 18s, someone points out "you shouldn't be using those bindings if you don't know the answer". Not true. There is no reason why you couldn't use the FKS180s if you run a DIN setting of at least 8 and want a super durable pair of bindings. Hell, I almost bought them and I run DIN 9 (I went with the 14s because they are lighter).
Rant over.
To the OP: You will be fine with either the 12s or the 14s. The Pivots are my favorite pair of bindings.I got my first pair last year and this year I didn't have to think twice when looking for bindings to mount on my new skis. Pivots all the way.