I really like the expression of her face and lineart is nice too. Proportions is normal. But coloring need some improvement. Colors are favorable, but it needs more shadows and highlights. I think that background is not very suitable for this theme. It may be not so bright and blend with the foreground. I also think that a broken heart - a sorrowful theme and sorrowful painting should be more pale and even darker.
I love your idea so you just need to work on your technique and improve. In general, the picture has made a good impression, but still needs tweaking in the plan painting and color combinations.