The speaker starts by admitting a small mistake: they thought they'd planned things out, but maybe not as well as they believed. So they decide to think again, out loud, and let the thoughts spill out where we can watch them. It's a playful, slightly sheepish opening.
From there the poem seems to lose its footing on purpose. The speaker is running late, distracted, and the language gets tangled in itself, with words like "attraction," "distractions," and "subtractions" chiming against each other. Sound often seems to drive the lines more than sense, which fits a mind that's wandering. The last stanza drifts toward advice about a "great professor" and the trials ahead, but it ends by circling back to what was "already said," as if nothing new has been learned.
The mood is light, wry, and a little scatterbrained. The speaker seems amused by their own mental clutter rather than upset by it.