New Puppy questions

[wellsnmj]

So I posted up yesterday we got our first as a family GSD Riley a couple of days ago ( I had one growing up a big black and tan male 120 pounds over 6' standing on his hind legs ) and have a couple of questions. Her lineage consists of : Her mom is a 80 pound sable her dad a 110 pound black and tan and her maternal grandfather is a 120 pound black. Most of the dogs are DDR dogs from Germany back 2-4 generations. She has a Vet apt on Tues ( quickest we could get )

1) she is 5 1/2 months but is only 18 inches at the shoulders and 25 pounds I know she is a bit small and some DDR's an take up to 36 months to hit full stride but is she underweight for her height. I feed her three times a day and she eats perhaps 1/2 cup at most per feeding ( I give her 1 cup but she eats half or less and refuses to eat not at meal time even when food is left down ) .

2) she is a "Black" but actually more chocolate then black is this normal will she darken up with age?

Thanks in advance for your input!