I love it, too. It also has a lovely meaning. I know three, but one lives in Britain and two in the US (the one in Britain is 10, the ones in the US are 11 and over 40).
I also know a dog named Phoebie. It's not the spelling I prefer, but it's pretty as well.
I think it's extremely common in Britain according to the charts so I might not use it if I lived there. There's always
Belphoebe. You could call her
Phoebe and if there's another one she could go by
Belphoebe or maybe
Belle or
Bella.