The speaker of "First Love" is a male character who has just seen his first love, and the "stole" the heart "complete" of the speaker, and when he is looked at by her he is unable to walk and suddenly his "life seemed turned to clay." A beautiful simile is used to describe the girl, when the speaker describes how her face "bloomed like a sweet flower" which captures the sudden impact of the girl on the speaker.
The physical reaction of the speaker in response to this first love is further elaborated upon in the second stanza, with the use of alliteration emphasising the beating of his heart as "blood burnt round my heart" and the onset of love robbing him of vision and clarity. The final stanza, after a series of rhetorical questions to underline the impact of love on the speaker, closes with the following four lines:
I never saw so sweet a face
As that I stood before.
My heart has left its dwelling-place
And can return no more.
In an implied metaphor, the heart is comparted to some kind of traveller who has left his home and is unable to return. This helps to capture the feeling of the speaker that the girl he is looking at has taken his heart forever more, and it reinforces the intensity of his feelings as he feels he will never be able to regain his heart again. This poem therefore captures the sweetness and the intensity of first love through a description of the reaction of the speaker to finding his first love and how his body is incapacitated as a result.