I am 47 and started with the violin just a week ago. Still trying to figure things out and create a solid practicing structure. My practice is a bit hindered by the fact that I have to worry about the noise. have a mute coming in the mail but it is taking so long!! :-). Anyway, it seems like for a nice practice you have to challenge yourself with a piece of increased difficulty on your 3 or 4 songs repertoire. I play everything by ear ( tt little star) and will be learning to read music as this goes ( i hope) . Does it matter how difficult is the piece? Where is the line that separates a difficult piece from a frustrating one in the case of a beginner like me?