Rescues will tell you it can take anywhere from 6 weeks to 6 months for the dog to feel comfortable. Somehow we got a really resilient herding mix who made herself at home from day 1, but even still some of her "naughty behaviors" (barking, leash pulling) didn't show up for around a month.
Congrats on your new friend! We adopted ours at 3 years old also, and it was perfect--no chewing, accidents, puppy crazies, but plenty of energy and fun
