
Your vet is the best person to ask, because s/he will know the prevalence of disease in your area. My vet won't vaccinate a pup before 10 weeks because of the need to wait till the maternal antibodies have waned, and the second is given at 12 weeks. At 6 weeks your pup should have been wormed twice by the breeder, so continue that regime, getting the appropriate medication from the vet.
I always advise owners to take their new puppy to the vet within a day or two of getting it, to register it with the practice and to make sure that it is healthy at the time of purchase. If the breeder hasn't done a good job the vet will be able to prescribe the correct worming and de-fleaing treatment then.