I think it would mean more for her to pick out her own setting. Tell her that she can pick out whatever she wants, and money isn't an object (if that's true - or give her a limit of ___ dollars). You can always just get a setting there and add a chain later too. You can get inexpensive chains at craft stores, jewelry stores, etc. And she might want earrings or a ring or ____. Who knows. Easier to have her pick put something she'll love.
That's what I plan on doing, since I'm very bad at making these selections

