Well, some yorkies' ears never stand up! Some yorkies will have both ears up, some will have both ears that always stay down, and some will have one ear up and one ear down!
My yorkie's ear were standing up when we went to pick him up when he was 8 weeks old. But, it varies from yorkie to yorkie. My sister's yorkie has one ear up and one down, and my parents' yorkie has both ears down. If your puppy's ears never stand up, don't worry...it will still be a doll and you will love it just the same! Also try doing a search on this site for "ears." There has been much talk about it and I am sure you can find some good information by doing that.
By the way, WELCOME TO YT!
This is such a fun site. Please post pictures when you pick your baby up!