You have a way with words that makes this poem enchanting to it's core. The imagery is phenomenal, cracked ice on dead grass, snowflakes to a drift. I find myself following this poem like an afternoon shadow.
This poem has some very effective images that seem to a trademark of your poetry. Images such as 'cracked ice on dead grass' and frost expanding on a window are so clear it's as if the reader is looking at them under a microscope. The descriptions of the muscles controlling your breathing are zoomed to a similar level that gives the poem an intricate, introspective feel that works very well and consistently.
To me, the poem is divided into two distinct parts: the part describing the person you are and the part describing who or what you want to be. The first part portrays a sense of safety and security, that you are sure of who you are and perhaps there is a routine to your life. The contrast is quite stark and for me its where the poem really gets interesting. I wonder about what you want to me: words such as still and dead indicate that you do indeed want to be unliving. But I also see a meaning that perhaps you want to be something beautiful in its own way: not something usual like a flower but something more independent, distant, slightly dangerous or even unwelcome: almost an anti-hero, a multi-layered entity. There is also perhaps a sense that you want exposure: the imagery of your breathing in the beginning is very internalised and in a way claustrophobic, whereas the frost has the huge expanse of sky in front of it (adventure, experience). Also if you are still, you can stop to experience instead of being seemingly pushed downward involuntarily (perhaps a signal for a settling for a job or getting tied down, dreams getting further out of reach.
All in all, any poem that gets me this into it is a good one and this therefore is no exception. Its a typical piece that leaves the reader thinking after the final word has been read, and although none of my interprations may be your interpration, it doesn't much matter because a number of them can work and that is usually the sign of a good poem. A very enjoyable read!