Flushing words down in the toilet

It has been a rough and confused period of time lately. I feel like I am living again the insicure ages of youth, when you believed something and denied it at the same time. I was pretty sure I was strong enough to think with my own brain, to be sure about what I felt was good or wrong, about the bad and the worst,...
Now I don't really know it. I like to have fun, sometimes. But I am also ambitious and I noticed I "dismiss" friends when they take away too much time from me. To be sincere, I have never been a good student. I don't like to memorize words and to lose time to write down numbers when it is faster, safer and simpler to use a computer.
It has happened with someone who had too much spare time, with another one who was too much a dreamer, and it is now happening again with someone who is not studying seriously. I believe I am strong: it is very clear to me where I wanna come to in my life. Not the simple marriage and save money for a lifetime to buy a ugly flat somewhere nearby Milan's hinterland. I don't wanna even rely for my happiness on another person. I wanna build something mine, something I will never lose but that I can share, something that nobody will ever take away from me. I wanna know cultures, have a project, go forward, learn new things, have a healthy lifestyle.
I am not focused in finding the love of my life, I am not trying to meet as much people as possible to spot my knight in shiny armour.
If it should happen, it shall! I don't think that browsing on the internet and flirt with every guy that live in the nearby could help the fate.

And now I have started this friendship that is leading into a teenager-again time. Where it is all about flirting, making friends, going out with boys.
The problem is that I do believe I have no more time to do it. I have to focus on my targets, which are (in order): to graduate and to decide what to do next, where do it,...
I start to feel uncomfty in my position: 24 years old, full of strenght and willingness and still waiting for my life to begin.
I have still a lot of exams ahead (see my previous post) and a 4 months long stage before my final thesis. I have to decide where to take it: in Italy near home, where I can easily reach the job place or abroad where I wanna work in the future?
And what about the engineers' exam? do I wanna take it? do I need it? do I wanna spend another year working for free to take this f***ing exam?
It's such a mess!

Plus, I am feeling uncomfty with my self because my strong believings are falling down.
Am I too narrow minded or is just 90% of the people who is concerned only about beauty, fun and sex? Why aren't they working to build something big in their life? Why are they just postponing the important decisions in their life?

Have they scheduled "I will be having fun until the age of 29 and then, since I turn 30 I will be looking for someone else to mate with"?
Let's make it clear: I am not looking for the love of my life. I am not looking forward to it. But I am not even interested in lousy relationship that leads to nothing but a waste of time. Perhaps my fault is not to be able to make something seriously.
I cannot go out with you just because I have nothing to do. I have to like you, otherwise I'll spend days wondering how it is possible that people like you live in that way, do those things and have the right to vote. All this would make me nervous and less confident than ever toward people.