That's not you. That's a model named Celistina ____, something. Tiew OR Teiw, I think. Might be misspelling the name? I forgot.
How do I know this? An old time Singapore girl tried impersonating her as well on the very same forums.
And yeah, as for determine if people are fake, Google Image search ---> Lil camera icon ---> Upload their picture (Then it'll search the entire web for other pictures just like it)