This discussion seems to be always too hard.
I am coming to realize that regardless of being profitable or not, doing what you love is the way to go.
Don't know what you wanna be when you grow up? Well... pick what you like to do most at this very same moment and go for it.
If you change your mind, you then can decide whether you should quit again and pursuit something else.
Another good reading on this line of thought is "The Dip" by Seth Godin.
Please fail. And fail a lot. But be sure you get into something because you love it and are willing to work hard for it to overcome the difficulties. Otherwise it may not be worth investing your time in it.