@MarcusAntonius,
MarcusAntonius wrote:
I have only read some Nietzsche back when I was 14 years-old and later found out his writings are not considered to be philosophy per se.
I don't know who told you this, but they're dead wrong. Nietzsche's work is definitely philosophy.
MarcusAntonius wrote:
What is philosophy and where should I begin looking for it?
To answer the first question, I'll take from Rand. She has a pretty succinct definition of philosophy:
"Philosophy is the science that studies the fundamental aspects of the nature of existence. The task of philosophy is to provide man with a comprehensive view of life. This view serves as a base, a frame of reference, for all his actions, mental or physical, psychological or existential. This view tells him the nature of the universe with which he has to deal (metaphysics); the means by which he is to deal with it, i.e., the means of acquiring knowledge (epistemology); the standards by which he is to choose his goals and values, in regard to his own life and character (ethics)—and in regard to society (politics); the means of concretizing this view is given to him by esthetics."
(Philosophy: Who Needs It, 2)
To answer the second question, I encourage you to read the Greeks, particularly Plato. Aristotle is a bit tough to get into, so I would put him off for later. Presocratics are also a good place to start.
As for more modern philosophy, Descartes' Discourse on Method is a good place to start. Almost everything written after him, philosophically speaking, is a critique of his position, so he's pretty damn important. The book is a bit tough, so you'll probably need sparknotes or something for a better explanation.
If you're in college, take some philosophy classes as well. It'll help. I think MIT and some other schools also offer online lectures, so that is always a potential source of learning material.
Hope this helps.