She is adorable.
For your purebred question its a good possibility she is a mix. Saying that-she could very well be a purebred just not bred to standard. She looks quite big in the pic especially being 6mo but its always difficult to tell in pics. You can expect her to get a bit bigger still.
She is a prettuy girl no doubt. They do have dna tests you can purchase to find out for sure if you're curious but...what doesn it really matter.