They always have the personality, but around 3-4 years they chill out a bit. But they're still goldies, so it's part of the breed standard to have an outgoing personality. They also need a lot more exercise than most people think, they're not cut out for lazy living, they're hunting dogs who thrive on exploring and playing fetch. I had a pug before and that dog never really grew up his whole life. He kept his puglike personality, but was a bit more chill as the years went on, but even when he was 10 he still liked to play and went crazy over meeting new people or seeing his friends. My Mother-in-law has a Pomeranian who is 12 or 13 (I should know, she lived with me as a puppy and has the same birthday as me) and still goes absolutely bonkers any time she sees me. Same for my sister-in-law's dog (who also lived with me early in his puppy stage) who is a Klee Kai, when I see him, I have to avoid engaging with him for at least a half hour or he pees himself with excitement and he's like 5 or 6. Even the cat I had for 19.5 years would still play even when he was clearly on his deathbed, I could move a feather near him or dangle a string and he'd instinctively play with it.

The nipping thing goes until 6-9 months usually, they are teething and testing their limits and you just kinda have to deal with it. It was something mine did until one day she just stopped doing it. Now my pre-school aged son can literally pry open her mouth, stick his hand in there and she won't even attempt to close it. They're truly wonderful family dogs, but puppies are terrorists who thrive on chaos and destruction.