I adore
Daisy but only as a nick for something else like
Marguerite or
Margaret.
My mother was named
Margaret and I think
Marguerite (nn
Daisy) would be a nice way to honor her. I also had a ggm named
Daisy (with
Daisy as the full name). I picture someone named
Daisy as bright with a sunny disposition (just like the flower). I also realize that some may consider
Daisy to be a rather loopy name. That's why I'd give her a formal name to fall back on.