I remember when they went back and showed his interaction during the anime, too. Yeah, he really botched that start. I suppose that’s meant to help explain why it’s such a slow burn romance. She refuses to acknowledge she likes a guy that started out treating her like a little kid, and it’s taking this long just to work past hang-ups like that on both sides.
Also, pretty sure this isn’t the first time they pointed out she’s been there three years under him.