Is she pure bred

My wife and I got this GSD from a breeder but now are questioning if she's pure bred. She's 11 weeks 12lbs and is just really small for her age. The Breeder didn't say anything about her being the runt, im just really concerned if she is purebred or not. We think if anything she is a Shepard collie mix.

It's pretty standard with buying from a breeder that you can meet the parents, see papers that prove lineage, etc. Did you do that?
My mom's friend got purebred chow chow's and she did visits with the parents while they were being weened, got to visit the breeder's place to ensure a high standard is present in terms of quality of establishment (basically making sure they aren't housing the dogs in a bad environment, well cared for) and how the breeders are as people, etc.
I mean, in general, if it's a great dog, breed doesn't really matter unless you paid out the ass for her to be a purebred.

Have to agree.
Ours is a gem. A collie. But picked up as a a stray.
Doesn't matter. Max is just Max. A big, gentle, tolerant fellow.

Looks pure bred GSD to me. What makes you think Collie mix? Is your pup registered?