I have a lovely 11 week old lab puppy who is doing really well (responds to basic commands, toilet trained, sleeps through the night, affectionate, etc). He’s not yet fully vaccinated so isn’t allowed on walks but we carry him for short walks every day (even though he weighs a ton!). However, he growls whenever he meets new people or when people visit the house. He does warm up eventually and is fine after a while but the growling is worrying and the socialisation window is closing. Any tips/reassurance anyone can offer?