Great looking pup, just as with my pup, I didnt know what a young St. pup at 4 weeks old looked like or it should weigh. My pup Sheeba wieghed about 5 pounds at 4 weeks old and from that point on she gained about 3 pounds a week until she was about 7 weeks old and then she gained about 5 ponds a week. Now she is about 1 year and 5 months old and wieghs about 96 pounds, the wieght gain is slow now, which is good , she is slim and she is growing up and not out.
If your like me and in seeing so many pictures of Sts, I didnt know they looked so different from short haired, to femals being so much smaller then a male is. There is so much of a difference in color in the dogs, some being heavy some being slim. But they make a great companion, Sheeba has to be with me every minute and sleeps on our bed, when I eat she eats. When I had surgery, she cried when I was in pain, that blew me away how she cried because she knew I was in pain.
I do know that my dog was so easy to poddy train, nothing to it, only took me taking her out side a few times and she went out on her own from then on at about 5 weeks old. They are very smart dogs , but they can get very bull headed and stuborn, but you cant help but fall in love with them.
Great advice here, hope everything goes well for you, great looking pup.