What I mean by one on one training is a trainer who is concentrating on you and your dog and will help you through the socialisation period, rather than taking your dog to a class. A muzzle will not have bad associations for your dog as she should not be scared at any time during this with a good trainer. She will probably be as excited to see the muzzle as she is to see the lead as they both mean you are going out to do some fun stuff!