My teacher says that the F minor fantasy is one of Chopin's hardest pieces. In general, you should probably stay away from late Chopin (even the F minor nocturne; although I have not played it, I would imagine that it's much harder philosophically and musically (though I hate to use this overused, ambiguous term) than many earlier pieces of similar technical difficulty). In my mind, anything past 1838-9 (ish...) seems much more difficult to make sense out of than earlier works. Early Chopin is beautifully comprehensible, but requires an almost Mozartean sense of clarity; the stuff in the middle (around 1833-1838) has a nice balance of depth and elegance, but ultimately it should come down to what you like.
I played the first Scherzo a year before I did the second, and although I have been told my final performances were quite good, I was never happy because they are sooooo often played, it is difficult to compare. In this respect, for me personally, lesser known repertoire is far easier and ultimately more rewarding than the really popular works. The Op. 1 and op. 5 rondos are both great in this regard (I haven't heard them in a few months, but I would suspect the op. 5 to be considerably more mature; but listen to them and see if you like them). The op. 16 rondo is by far the best (one of my favorite Chopin pieces), but disgustingly hard. Plus, even if not many people play it, you will never hold a candle to Horowitz. (
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I do think you can play the first Scherzo far better...). You could do a set of mazurkas, the Op. 6 is quite fine, but I am not very knowledgeable about many of the later sets. You could also play almost any of the concertante pieces, if you are technically ready. They are all beautiful, and good enough even without an orchestra... Those are opp. 2, 11, 13, 14, 21, 22.
Or you might end up like me... Last summer, I determined that this year and maybe even the next would be devoted exclusively to Chopin. Then I discovered Beethoven... <3 <3 <3
Anyway, I'm rambling. Ultimately just play what you like. As long as it's not waaaay above your level, your motivation will prepare you for most challenges. If you want a good introduction to ALL of Chopin, I cannot recommend Garrick Ohlsson's complete set highly enough.
https://www.amazon.com/Chopin-Complete-Works-Frederic/dp/B001F4YGUA/ref=sr_1_1?s=music&ie=UTF8&qid=1398536798&sr=1-1&keywords=garrick+ohlsson+chopin (when I got it 2 years ago, it was only $80... *sigh*).
I'm rambling by now... Feel free to PM me if you wish, Chopin was my first true love (until I started cheating on him with Ludwig

).