On the subject of fixed form

I was thinking a lot about this in class, and one of the posts below got me thinking again. It's interesting how much a fixed form of daemon can truly say about humans, psychologically. On one hand, it's a shaping of character, a knowledge of who you are, which is both positive and negative. It is also something over which you don't have that much control, since I don't think Pullman ever said that one can choose what their daemon stays as -- the daemon has a will of its own. In some way, this makes me think of all the ways our personalities are influenced and 'shaped' by factors over which we have no control, upbringing, society, trauma, but which ultimately become an inherent part of our being.
In a way, I think a fixed form for a daemon is almost terrifying to me, it speaks of something which cannot change, something that is so fixed and immobile. On the other hand, perhaps our souls and our personalities really are that way - and since no animals are truly 'good' or 'evil', no daemon is good or evil. All the same, there is something about the finality of this transformation that makes it difficult to wrap my brain around - hey, I wish I knew what I was when I turned thirteen or fourteen.