TOO EARLY!!!
You know I would be Completely fine with all of this happening, on the SECOND OUTING, these two have. The convenience store arch doesn't count.
If they went, and enjoyed some manga, went back home feeling nice about everything, THEN they do something else or go back to manga cafe again and the 3rd wheel appeared, that would be fine. Main girl gets a crisis of confidence and actual progress is challenged? Fine. But have some confidence to begin with.
But you're not building the two main character's relationship, nor a foundation to be challenged for the girl, by causing her to run off crying THE FIRST REAL OUTING!!! Horrible pacing, so frustrating to me to see this go this way. I don't want "chase her down in the rain drama scene #5 oh the feels" I want the romance to progress so it's worth feeling about.