Hi Nic,
Great pic. of Johnny Dep! I think he is both very good looking, and a great actor.
I hope you will forgive me for saying this (and remember that it includes me when I was 17 too!) but I think part of the normal, natural teenage phase is being on the self-centered side.
Though I do note that you scored very high on the "selfishness" quiz. Even so, sometimes (not saying always or with you here) when we believe we are a certain way, it can influence how we would answer to these types of things.
I also think the teen years are a time where it is natural to dream and fantasize about what life might offer. I think a lot of teens have fantasies about being famous singers, actors, sports stars, etc. at some point. I seriously wanted to be a famous singer or a model! I can't sing so that took care of itself, and I was too self conscious to pursue modeling at that time (shucks!) I
still imagine myself in George Michael vids hehehe (he did some good ones, always giving models great parts)..
In fact, so many of the things you mention seem like a natural part of the teen phase in life. Liking attention, being manipulative here & there, over exaggerating some stories... Heck, even many adults are still doing these things!
You also seem consistently concerned about being NPD. A full blown narcissist is often too emotionally enveloped in the very disorder of narcissism to realize or wonder whether they are a narcissist, and then to worry about it, like you are doing. So many of them act oblivious that they are doing anything wrong. It is all about projecting blame outward, which you do not seem to be doing.
The only thing that caught my eye really, was the you said you'd never been able to feel empathy/place yourself in another's shoes. It would be a concern if you acted out as a child in say, hurting animals, or violently with people. On the other hand you may be more empathetic than you realize. Someone who knows you better might say "remember the time where you"..., and you might say "oh yeah- I guess that was me being empathetic"... So, it's hard to say just by your diary on that one.
All in all, only from what you have written about yourself, you don't seem NPD to me. You could merely have some narcissistic traits on the strongish side (without having the disorder) and you might not at all, either.
I think you are very smart, and doing the best thing for yourself. That is to keep reading about human behavior (because you seem to find it interesting), and keep being very much aware of aspects your own self in an introspective way. You can't go wrong with this kind of self learning. So many people don't start being introspective until the 3rd or 4th decade in life. You are very wise to be beginning now.
Try not to self judge or worry too much either. Just observe with an open mind and without expecting to find a particular thing, and over time, "who you are" should become more & more clear for you...
You can always keep & grow aspects that you like, and work to change things that you'd like to be different
Best wishes...
BT