In reality, they're still in their second year, and haven't gotten to Valentines since they started interacting. These extras do not count as time progression.
Also, page 3, panel 3... I feel like that's a face that says 'Yamada will remember this' for when the real Valentines chocolate arc hits. (to be fair, I should know, as I already watched the anime, but I can't remember if she did put anything to words then, or if this is more a thing of her remembering that for when it's time to properly confess in volume 8, which is what the final segment of Season 2 of the anime was adapted from).
Oh, wait, no, yeah... I do remember. The cupcake thing she ultimately gives him has kanji on top. So yeah, 'put to words' was indeed a thing she remembered.