Oh? Please, Madam
What Izuku rejects is the opportunity to be Katsuki's SIDEKICK. He doesn't reject being a hero or competing with Katsuki. He rejects working FOR/UNDER Katsuki. Which is hilarious because Katsuki accepts (apparently multiple times) showing up as a guest lecturer to help out Izuku's class. Katsuki tells Izuku that "If everyone is special, no one is special," which has the potential for SO MUCH DOUBLE MEANING. But what there is no ambiguity about to me is he's basically telling Izuku "Hey, notice this. I'm treating you special. You're special to me. NOTICE."
It's also implied that Izuku sees Katsuki more regularly than he sees most others from their class, which is emphasized by the previous chapter when Aizawa complains to him about Katsuki's behavior in public affecting his ranking. Katsuki basically tells Izuku he needs to start thinking about himself more, and he also ends their final interaction with a "See ya [later]." Katsuki is NOT talking about Ochako, but Izuku takes some of his advice as the impetus for going to talk to Ochako (specifically they just wanna talk more after the dinner since the dinner is now over and they didn't get to talk). So what was Katsuki thinking of? I personally read his "See ya later" as "You'll figure it out, just go handle what you gotta right now and you can catch up to me later."
Hilariously, Izuku calls Katsuki out for being the one to say "If you don't start thinking a little more highly of yourself, you won't notice the things you should." Izuku's response is basically, "Look who's talking." Again, the potential for double meaning here is painfully obvious. He could be referring to SO MANY THINGS and we're meant to infer what that is. WE GET TO GUESS. Izuku could be saying "You did stuff just as bad as what you're saying," or "You're STILL not noticing something, Kacchan."
And Izuku taking inspiration from Katsuki's words to go talk to Ochako is meaningful in another way--IT MEANS IZUKU LISTENED TO HIM. Katsuki is having an influence on Izuku in a way to improve who he is just like Izuku did for him in high school. Izuku takes Katsuki's advice seriously. NO ONE HAS EVER GOTTEN HIM TO UNDERSTAND THIS LESSON BEFORE NOW. It ends with Izuku and Ochako deciding to talk more, but what it shows us is the beginning of Izuku considering himself more. If Izuku follows Katsuki's advice long enough, he'll end up back in the competition with Katsuki just like Katsuki expects him to. That is just as easy of a conclusion to make from the theme of "inevitability" that Shouto gives us (and that Izuku also takes to heart).
This ending implies that inevitably Izuku's gonna catch up again, basically. Things will continue to change. So yeah, we get a beginning where he and Ochako meet up to talk, but it's just a beginning. It's one night of chatting. They're seeing if something's there now (which kind of implies that there wasn't much there before), but it's left open-ended. And I think it's left open-ended what happens with Ochako on purpose because anyone can read how that ends up however they like. You just have to decide as a reader what's "inevitable" for Izuku Midoriya from this point on. Me? I've decided Izuku is taking Katsuki's advice to treat people who mean more to him better. Ochako is just the beginning. Izuku has other people in his life he needs to show love to as well (because that's what this is, Izuku is learning to show people that they're important to him, that he loves them, because saving people doesn't do that--he saves EVERYONE). And then maybe he'll start to see how the people who love him treat him special too, like guest SPECIAL (same kanji) LECTURER KATSUKI BAKUGOU.
tl;dr there is a lot left open to interpretation and it's probably on purpose, read the chapter however you like, just like we did with the last chapter.
...and my interpretation which is the correct one is that Katsuki tells Izuku, "Here let me show you how to love people, damnit!" to give him the character development everyone has been begging for him to have for years, to realize that saving people doesn't mean they're special to him if he's known for saving everyone ever, so like, maybe go show them you care in OTHER ways, Izuku, and also I'll be waiting right here for you to come show you love me you jackass (and he does, he does come show him that)
