Because she actually wants to go on the date and it's easier to miss on purpose than guarantee for sure getting it? Idk, it's awkward af but kids are awkward and there's all kinds of dumb gender stuff tied up in girls asking boys out directly so it's forgivable imo. Also, giving him an opportunity to be jokey and fun, "oh noooo, how could I have missed wink", show that he doesn't take himself too seriously and can play around. Which he failed lmao. (Yes yes I know it's fake)