@bejad007 again I am not a gyaru scientist but if search that term on google images only a couple look teenager, most look upper 20s and the very first image looks the same age as twin fang mom.
Gyaru is a fashion subculture with a whole bunch of separate sub-subcultures within it, there's nothing particularly contradictory about an adult woman being a gyaru
Inasmuch as there's nothing contradictory about, for example, your mom being into goth or punk fashion