I'm always talking to myself!
Well, not so literally. 
I'm talking to somebody [who is not there] about my life. How I went through bullying, through cutting, through bulimia... I talk to thin-air as if I were on a talk-show, doing an interview. 
I normally fantisize about being famous, and I know I can be one day,  [I'm already in the business and have been in several Disney movies] but seriously guys... Am I crazy?
I whisper to myself everyday and answer interview questions for at least thirty minutes! 
I've never talked to myself as in speaking in general. I don't say: "yes my day went well, you?" It's never conversation. Only answers.
Can you guys help me stop if I'm crazy? And if it's normal, is there a reason I talk in answers and of the future?

Crazy is a somewhat subjective term here. We can't really know for sure if you are crazy simply from talking to yourself in that way. Is it completely normal? Not really... but I wouldn't say you are definitely crazy simply for doing this unless you start to blur reality while doing it.

Maybe you just need some friends or someone to talk to.

I would say that's not crazy at all considering you know it's not real and are aware of reality. I do the same thing, like I'm giving an interview about this book I'm writing or sometimes I it's just about my life in general, it's normal to fantasize about the future that seems promising and happy considering the things you have been thought.

I would say that this is completely normal. You talk in answers because you are talking to your conscience. You are consciously asking yourself a question or taking a mental note of something you don't want to forget. BTW, what did you mean 'answering interview questions for at least thirty minutes'? After the interview or during?