The average women's height in China is recorded as 5' 2", but it depends where you are. All around the world, the farther you go from the equator, the taller people are in general. In northern China, 5' 5" is not uncommon at all.
A second factor is age. Several decades ago, many people suffered from inadequate nutrition, so many middle-aged and older people are shorter. Now that most Chinese kids are growing up with enough food, Chinese people have been getting taller with every generation.