older and more-educated citizens are less likely to remain ambivalent about their country identification and are less likely to select Taiwan as the name of their country.
This implies that both country and national identification are solidified as one ages.
Liu, F. C. S., & Lee, F. L. F. (2013). Country, National, and Pan-national Identification in Taiwan and Hong Kong. Asian Survey, 53(6), 1112-1134.