Unless you get to see real ID of a girl, how can you tell if this Chinese girl is really young? We all know Asian women tend to look much younger vs western women naturally, but with make up, botox, plastic surgery etc all women these day can look like their in their 20s while their real age is like in their 40s or even 50s.....
Now unless you straight up ask the girl what's her age and you're assuming she is telling you the truth (girls lie alot btw), would you really know??