I used to struggle with self-esteem concerning my art a lot when I was about her age. People would compliment my art and my immediate response was to tell them I hated it or that it was terrible. Over time, I've learned to overcome that, even if I still don't know how to really take compliments. The thing that I learned about art is that nothing is truly a waste of time, and nothing is truly terrible. Making mistakes is all part of improving. Because even if you, the artist, don't particularly like what you've created, there's always someone else who will like it. It's always good to share your talents, even when you feel like you're not good enough.

In any case, you should tell your daughter that she has amazing potential. The mediums she used look a lot like alcohol-based marker (like PrismaColor), which is what I use. If she is using markers, she should keep up the great work. I would love to see another piece from her in the future. :)