When you get more skilled/better at playing your instrument, you will still play the piece badly because you didn't have the technique when learning it. The faults will stick.So you will probably regret learning the piece because you will have "ruined" it for a future life.
The problems that will occour is mainly:When you get more skilled/better at playing your instrument, you will still play the piece badly because you didn't have the technique when learning it. The faults will stick.Also, you WILL develop faster by learning 5-10 pieces you can actually play rather than learning the opus 111 Beethoven sonata the first year of playing piano (just an example).