Well, one way to figure it out is to think about it. But obviously, that usually doesn't work. The other way is to try out things.

You can not know what to do with your life because you don't have full information about what all the possible paths are, and what they offer. Then you just need to learn more about more subjects.
But even if you know everything, it may be that you don't know enough about yourself to make a decision. I guess the latter one is the hard one.

I don't know how students loans work in Italy. It may be better in some cases to not spend your limited student loans studying a subject you are very unsure about.

Some people say traveling works to find out what you want. I am not so sure about that.

The idea of taking a year off, I always suspect that doesn't work very well for many people. You should only do that if you are the type of person that is already very outgoing, active, engaged, social, I feel.

When people are really drifting, after having failed one or two studies, some people say; "Go work that job you will end up having to work without a degree and see after a few months if you can phantom working that job for the next 25 years."

For some people, motivation only kicks in out of fear.

Also, at age 18 you can't be sure you are bad at something.

As for getting an arts degree, I think this is the best advice: