Based on her dialog at the castle, I think you're at step 4 of her events: https://renryuu.miraheze.org/wiki/Ryoko#Character_events_sequence
"Event starts by talking to Kirsten in the bottom right corner of Calbridge Stronghold. Requires the first public health upgrade (construction of the clinic). "
After that event is done, you can talk with Ryoko in the sleeping chambers for the next step, and then the part at the city board with the 'The Meeting' quest will begin.