“When You Are Old” is obviously a very romantic poem but it is also about aging.
The poem When You Are Old is a romantic and aging piece as author William Butler Yeat is addressing his love to a girl and telling her to imagine herself in the future. In the present time, this girl was loved by many guys, as mentioned in the first two lines of the second stanza. Yeats claimed that all the guys loved her for her looks while his love was unique. Yeats wants the girl to think about herself in the future because when she is old and not pretty anymore, she will no longer be loved as much. However, Yeats wants the girl to understand that even though she is no longer pretty and no one loves her anymore, his unique love is still there for her.
Your interpretation of this poem makes much more sense than my own, unless Yeats wanted to leave this up to interpretation. I interpreted as time goes on, the spark is gone from their love, but rereading the poem and looking at your analysis now, it makes sense as he tells her “When you are old and grey and full of sleep, And nodding by the fire, take down this book” to remember how prominent her beauty was and even as she grows old, that fact is still there. I didn’t grasp that until your analysis, which is very well interpreted.
I agree with you that he’s telling her as she becomes old her beauty will not be the same and there will be a lot of man who will stop liking her. However, he is trying to let her know that he is not like the others he will always love her no matter what. He is also trying to let her know that for him she will always be beautiful no matter how old she becomes.
I agree with you that the poet is arguing that many men would love this person for their looks, but eventually, with age, good looks fade away. The poet is more understanding and wishes to spend the rest of his life with her since he fell in love with not only her looks but their emotional connection. His unique love is unmatched from others who only want her for surface level reasons.