Final answer:
The repetition of "I was fifteen" in a literary text typically serves to emphasize the significance of the speaker's age during a pivotal experience in their youth, framing their decisions and perceptions within the context of adolescence.
Step-by-step explanation:
The repetition of the phrase "I was fifteen" in each stanza can indicate different purposes based on the context of the literary work. If it is a coming-of-age narrative, this repetition is likely to indicate the point in life at which the speaker encountered a memorable experience. It highlights the innocence and impressionability of youth, as well as the struggles and decisions that may have had a lasting impact on the speaker's life. The repetition of age here serves as an anchor, reminding the reader that the speaker's perspective and choices were those of an adolescent at a pivotal moment in their development.