Well the previous owners told us she was 17. We found a month or so later that a friend of the families had owned her a while back and that she was actually 21.
So no, we don't know if she is purebred QH. The people who had her a few years before the people we bought her from said that they knew that she was definitely QH, so we're going on what we've been told by some of her other owners. I don't know how that works, considering, like you said, she's not registered so we really don't know if she's a purebred or not.