Now, now. Before you reach for your "Team Edward" tee shirt, that's not what we mean here. In this poem, the speaker refers to a few different kinds of twilight. He refers more than once to the time of day (either at sunset or before dawn). This is a short poem, though, so we can't help but think that twilight is important to this poem's message. Our speaker is getting older and thus approaching the twilight of his time on earth. Twilight signifies the end of the day, and in the same way implies that the speaker is reaching the end of his time on Earth. Bummer.