Does the princess dress count as Hanfu?

Not exactly. Princess skirt is a kind of dress, which has the style of tube top and suspender. It is gentle and lovely, suitable for young women. Hanfu is a traditional costume of the Han nationality, which prevailed in areas inhabited by the Han nationality from the Han Dynasty to the late Qing Dynasty. It is the embodiment of China's "dress country" and "etiquette country", bearing the outstanding craftsmanship and aesthetics of the Han nationality. Princess skirts are not counted because of their different types.