Actually, he does know from the lie detector test that she wants him to punch her V-card, he hears from her mother that she's been "practically chewing her nails off all week thinking about today," and that "she was crushed when they canceled those pirate cartoons you were going to watch together," that "Yesterday she spent the whole day whining and brainstorming plans for today," she tried to bake a cake that got ruined, she "tried to draw one of those Japanese comics of hers for you, but she wasn't happy with how it turned out, so she tossed it away," and "she spent a good three hours this morning trying to straighten her hair and comb it just right." The mother then talks about what a big crush Nova has on him. Yes, the MC knew this was a big deal for Nova.