I really like this.
I hate how the comments be like "fuck this fmc for not saying anything or saying yes' but this is consistent with the FMC and what her personality is. She gets thrown this confession out of nowhere and she, a true introvert just freezes. It's hilarious but I think it shows room for growth.
Instant romance isn't always the best, I don't get people who begs for it even when it doesn't match the tone. Other series can do it because they consistently hang out with each other and genuinely like each other. These two barely knew each other before ch 1 and has only slowly gone on like a few outings together, in a sham relationship. They only started getting somewhat closer.