My first name is
Starla and I'm sometimes called
Star as a nickname. I don't particularly like either
Starla or
Star, but if pressed I'd say I prefer
Starla over
Star any day.
Star is tacky-sounding in that it's in-your-face-wannabe-glamorous, the kind of name a certain type of girl might choose for herself as a stage name, or to make herself seem more glamorous than she really is. It's kind of like the old adage that "People who really shop at
Tiffany's don't usually name their daughters
Tiffany" (which is why it was so odd that
Donald Trump's daughter is named
Tiffany.)
Estelle and
Stella are both very pretty names, and
Star might work as a nn in purely the name-nerdy sense, but really,
Star as a nn for those seems too nerdy and self-conscious.