Yes, big dogs make you think they are older mentally than they really are. Small dogs are practically adults by the time they are one, big dogs don't reach that until at the very least two and a half, most of the time it's three and even four years old. I do have to agree that she is a bit chunky looking, and maybe you could start taking her for walks with another person, then have that person hold the leash when walking, and hopefully you can get her attached to this person so they too can take her for walks in case you can't. Was she properly socialized as a puppy, because she sounds a bit scary...