The speaker of the poem "Hanging Fire" is a fourteen-year-old girl. During the poem she seems to have the curious, inquisitive nature of a child. She wonders, for example, whether she will "live long enough / to grow up," and she wonders what will happen when she dies. This inquisitive, speculative tone implies that although the girl is now a teenager, she still has some of the natural wonder characteristic of younger children. The speaker is, after all, still only a young teenager.
The speaker's inquisitive, curious tone sometimes seems to become anxious. The girl seems anxious about typical teenage issues, such as the boy she's in love with being immature, and her skin "betray(ing)" her. She is also anxious about having to learn to dance "for the next party," and about "wearing braces" and having "nothing to wear tomorrow."
The biggest source of the girl's anxiety, however, seems to be the fact that her mother has locked herself inside of her bedroom. Indeed each of the three stanzas concludes with the same lines:
and momma's in the bedroom
with the door closed
The mother's absence seems to cause the daughter anxiety because the daughter has nobody else to talk to about all of her teenage worries. She would presumably like to talk to her mother about the immature boy she is in love with, and about the dance that she has to learn. The mother, however, is unavailable, and it seems as if she refuses to come out of her bedroom. The daughter is thus unable to resolve any of her worries.