Hello Rui!
Entrepreneurship is a big step, most especially if you would like to do a start-up. You're going to give up on something just to focus on this. Not everyone who starts with start-ups are successful so you must have PLAN A, B, C, D, E and so forth. ^^
I do hope that you are going to be succesful. Steemit is a great community as well for you to share all your learnings and updates on how your project is going. I wish you all the best.
You are right. More them 80% more than 80% of startups fail. I'm trying make steemit my plan B.
Lets see if I can do it :)