When all at once I saw a crowd,A host, of golden daffodils; (lines 2-3)
You don’t think about verb tenses through much of the poem. It reads like a straightforward narrative which, though not set in the present, still has this present-y atmosphere to it because of phrases like "all at once."
A poet could not but be gay,In such a jocund company: (lines 13-14)
The poem could have worked just fine if it ended here. Sad man becomes
happy: a perfect plot. But no, Wordsworth has to be Wordsworth and add
more layers of complexity.
For oft, when on my couch I lieIn vacant or in pensive mood, (lines 19-20)
The final stanza hits us with a surprise: the daffodil scene wasn’t
something that happened yesterday, or even last week. It happened a
while ago. Now the speaker is giving us a memory about his memories.