According to the database, it first came to people's attention as a girl name when a character was named this in the movie The Blind Side. Interestingly, the actress who played
Collins was named
Lily Collins.
The film was set in in Tennessee, and the South actually has a long history of using family surnames as first names for girls. So it's not as new of a name as non-Southerners might think.
I'd be interested to see which areas of the US use this name - maybe it's still favoured in the South.