Let’s be patient with Saki. For us, it’s been slowly building up for years. It was only like two or three weeks ago when she was still planning to take her sexuality and her feelings to the grave. It hasn’t been 24 hours since her first coming out + love confession ever. Just one of those is nerve-wracking enough on its own. Her most optimistic outcome was probably just that Kanon would accept her feelings but would still need time to decide how she responds.
Yet, before she even gets the words out, Kanon kisses her, then confesses her own love, and that’s so far outside the realm of anything Saki ever expected or dared to dream of. What, how, when?! Forgive a girl for questioning reality itself and even taking an obvious joke at face value.