Here's why:
* The focus on the tooth: The poem revolves around the excitement and anxiety of losing a tooth, a common experience for young children.
* Simple language: The poem uses simple, child-like language and vocabulary, suggesting a young narrator.
* The "Little Mouse": The poem mentions a "little mouse" coming to take the tooth, a common childhood belief.
While we can't be certain of the speaker's exact age, the poem's themes and language point towards a young child experiencing the milestone of losing their first tooth.