What i wanna know is if you guys think i know enough to start getting to know how to work with Slick2D and how to make games in it, or i have to learn more (maybe more than in that tutorial is) to get to that point.
It's hard for anyone to say how much skill you've developed just from a link to a tutorial you looked at for a week. It's also hard to say whether or not you're equipped to tackle a project of undefined scope.
It's really easy to underestimate the difficulty of a programming project-- and it's especially easy to underestimate what's involved in tasks you haven't successfully undertaken before. If your programming experience is one week's worth of following tutorials, that's going to be a long list even for a very simple game. For what my opinion is worth, if you are still looking exclusively for tutorials and have not completed an original project of your own (similar in scope to the 2D game you'd like to make, save for graphics) then making any 2D game might be too ambitious.
Are you dead set on making a 2D game, and no other type of project will do? Is there a particular style of game you're thinking of making, or a similar game you might be interested making a clone of? Answers to these will help figure out what might be a good project for you.