Be honest with yourself, don't pick pieces beyond your range. Your ears will always be bigger than your technique. Don't worry about technique too much, high musicality and incredible technique are correlated, so worry about making music first. Don't play faster than you can perfectly (musically). Learn as fast as you can. When you pick a new piece, learn the notes the same day and memorize the piece over the next few. If you can't do that, the piece is too hard, or you're practicing wrong. Get a good teacher. Don't take unmemorized music to lessons.
The three most important virtues to a pianist are integrity, respect and honesty. Integrity to your musical goals, respect for the music and the composer, and honesty with yourself.
Remember, pieces are either easy, or impossible at the moment. I suspect that for you, that ballade is impossible at the moment.
***edit*** I re-read your post, I don't know why I thought you were trying to play a chopin ballade!
Oh, and to save yourself some trouble, much like you can't work out for 24 hours consecutively and expect results, yet you can do so over 24 days and see drastic changes, the same will be true of pieces. Unless a piece is far below your abilities, you won't get it "up to speed" on day one, so don't bother trying. Not even on the easy parts.
Most importantly, success at the piano is ultimately determined by who you are, not what you can do. Improve as a person and you'll find your playing will become better correspondingly.