What am I and what can I be?

Well, this is an important question, as it has been bothering me for a long time.
When I was young I was never asked this question nor it has occurred in my mind one single time. I always thought: when I grow up I wanna be this or that, I wanna be like Harry Potter, I wanna look better, I wanna be rich, I wanna be happy. Despite all of this, I didn't become HP, rich or happy... So, I followed a diferent path.
There are two types of characteristics defining us as unique persons: the physical and the psychological.
The physical ones cannot be changed; they develop based in genetics and only a small part depends upon the environment (like acne, etc.). In order to prove my point, see the case of identical twins: they may have the same genetic code but they are still physically distinguishable by a careful observer.
The psychological are still an enigma for me. They are dependent upon the ambient, but are they dependent on the genetics? I think so. I believe that some characteristics come from the brain structure and physiology, which are defined in DNA. But, the majority of our psychological aspects are contingent on the family we were born into, the friends we have got, etc. We can change this: families are dynamic, and friends are chosen.
Now, in a certain point of my life I feel I don't know who I am. I think I may have changed to much and became a different person, one I really am not programmed to be. Is that possible?
How can I meet my true self?