You die.

You order the green tea.  Kirika has the first sip and says it's very good for green tea in Paris.  You take a big swig of it, and somehow manage to choke on a few stray tea twigs.

Kirika doesn't actually know CPR, but gives it a good try anyway.  It just causes your death to be a little more painful.  She calls out for help, but it's too late.  She leaves before it becomes too big of a scene, and actually feels bad for you.  Later that evening, she asks Mireille about enrolling in a CPR class.