My parents won't let me get FB or Twitter?

[Brt]

Well there is your answer in your own question.

You said that you live in China where FB and Twitter are prohibited, which means that anyone using these online applications are government rules. With this, it is very likely that the government might think maliciously of you in a way that could warrant you being monitored 24/7.

This in turn may in turn negatively affect opportunities that could come your way.

If your parents think of its this way, the may just be concerned about your future.

On hindsight though, are you of the appropriate age to have a facebook account? If I remember it right, there is an age limit allowed in using FB.

Maybe you should wait when you are at an age capable of standing to the consequence of your actions on your own before you go against the wishes of your parents... best of luck! :-)