If she is that light she likely a mix of one of the small breeds, Netherland Dwarf (ND) being one of the most common, but Mini Rex, Lion Head, Mini Satin, Polish, Tans and Britania Petites are other possibilities.
Her head looks fairly blocky, similar to a ND, but her body frame seems to be more racy like a Tan or Brittania Petite and I have seen many maneless Lion Heads with this bone structure and think this is what she is, or possibly a LionHead X ND