Hmm... what do I think about dogs sleeping in my bed?
Perhaps the picture below will help.
They all love sleeping on my bed with me and I wouldn't have it any other way. Of course they are not allowed to sleep on the bed until I know they are potty trained.
And they have to stay on their side of the bed which they all learned quickly. And they have their blanket they stay on, I don't let them on my sheets on my side just in case someone was to have an accident.
If you want your yorkie to sleep on the bed with you then go for it. I don't see any reason why they shouldn't.