Hi Mandy
It's difficult to advise on problems with aggression over the internet when none of us knows Molly or can see how she behaves. It sounds very much like fear aggression ie she uses aggression as a defence mechanism when she is frightened or alarmed by something or someone. Fear aggression can sometimes be hereditary or caused by lack of early socialisation (probably not the case here). My advice would be to consult your vet to make sure there is no physical cause for her behaviour & if not, ask for a referral to an experienced behaviourist or alternatively look at finding a reputable trainer/behaviourist for yourself (try
www.apdt.co.uk) You do need professional help I feel as fear aggression can be a difficult problem to overcome. I would also suggest you contact your breeder - a good breeder should be willing to support & advise you, particularly as Molly is only 6 months old.