What does the sunflower symbolize in william blake's "ah! sunflower"?

The sunflower represents a person no longer young and thinking about life.

Explanation:

The poem shows that the sunflower is enumerating the footsteps of the sun, this implies the passage of time to the speaker and this passage of time reveals that the speaker is aging and observing the passing time while reflecting on life.

In addition, in one of the lines of the poem the speaker reveals that "the traveler's journey is done" represents the end of the youth of the speaker who is getting old and tired.

There is internal conflict present in this passage: "This, I thought, was the moment of decision, which was to rob me of, or bestow happiness on me for ever." This shows that this person is struggling to make a decision.