That overreaction that if you didn't date before 15 you are loser (〜 ̄△ ̄)〜 Girl, you have a whole life ahead. You should focus on studying and friendships at that age.
The ML is acting like a kindergarten kid. You like a girl, just confess or at least act nice. The FL is lucky that she has no self-esteem issues. The way he is acting would have destroyed someone if that one had no confidence in herself.
Not every manga can pull this off - misunderstandings that are not annoying, but fun material. It could have continued for more chapters. Too bad it ended. T.T
The ML is a green flag, the relationship is healthy, the synergy of things just flow. The action part wraps up. I only wish for updates.