introvert or extrovert ??

A big question to me, as I am supposed to be a frank guy to my friends a shy guy to strangers, isn't it awkward to see a person first time and you just started to talk like you have known him for years. As it looks funny to you, but sometimes I am really confused whether should I started a conversation or just stay calm.

We all know words are the most powerful weapon to express yourself, many people also say that, just say it out man, whatever you think at least you will be free, but still I think it's not right to say anything without sensing the situation, but sometimes time past by and I was still sensing the situation, yaar what to do ?

What kind of my nature, am I an introvert or extrovert ? I think I am still thinking about the situation in this question, isn't it ?