didn't use pigtails until now? A true tsundere lives and dies on that hill.
Smiling openly after a compliment is obviously forbidden.
You need to know your basics. Those are fundamentals missing right there. And don't get me started on that proper greeting you made when entering the room.
Childhood friends in a romcom are usually only at risk of losing when at least one rival is introduced in the first chapter (or two chapters, or however long it takes to finish introducing the premise). There are exceptions (especially things that slowly snowball away from a comfy two-person romance into giant disgusting soulless harems), but they're comparatively unlikely!