In ten years, she is going to remember that you thought enough of her opinion to let her have one, and you followed through on what she decided.
You have shown her that you can tolerate a difference of choices, and whether you can appreciate it or not, you have taught your strong-willed daughter that she has a right to an opinion and that when she makes a decision, there is a reaction to it.
In ten years, she will look at that quilt and love her choices as much as the day she picked them out.
And, if her tastes have changed (or, more likely) her needs call for a different solution, you may find her quilting a different pattern with much the same colors.
I like the quilt. Maybe I wouldn't have thought to put those colors together, but they look just fine ... and, while green is not one of my first choices for a color on anything other than grass for my cattle - - the shade she selected looks perfect to me! <wave>