She does seem like its possible she could have a little something else mixed in there! But, she looks like a sweetie!! Also, I dont know if it matters to you or not, but it may not be too late to get her ears to "stand" by taping them...some people like them floppy, some like them straight up!
Yorkies do come in all shapes and sizes, so it is very possible she is full blooded. We have a 5 month old that was a "blue born"...He is almost snow white and has hazel eyes, and I am 100% sure hes a purebred. Regardless, just love her forever, no matter what!!!
Oh, and by the way.....Welcome to YT!!!!