klinka

1. colloq. little girl; young girl; kid
   Kad sam bila klinka, stalno sam se penjala po drveću. — When I was a kid, I was always climbing trees.
   Ona je još klinka, ima tek petnaest godina. — She's still just a kid, she's only fifteen.

The male counterpart is klinac; said of a teenager it often sounds slightly condescending.