Why am I INTP?

I was pondering over the pros & cons of being an introvert and concluded that an extrovert would probably fare better in life. I prefer an 'E'. I'll have more friends this way. I'll get to learn new things and be exposed to much more instead of being cooped up in my own mind. This I don't like. The cooping up, and the lag time taken to react to a group conversation/ express an opinion.

Then, I came across this front cover:

I haven't read the book but I get the message. But then, it led me to think. Why am I an introvert? I don't think it's solely in the genes. It's due to environment, influences and exposure. So.. this means I can convert into an extrovert if I want to push myself along that direction?

I decided that I'll learn to change based on my earlier conclusion that I'll get to learn more by being with others. If I ever take a personality test again, I hope I get a ENTP or something similar. I must develop a liking to conversing with others, and not fear awkward silences/ lack of topic to discuss. I must read more to even manage a monologue if necessary. That's the extra step I need to take to convert to an 'E'. It's a chore, yes. But I'll manage. Let's see. :)